Do the common programs (for example: “ls”, “cat”) in Linux and BSD come from the same source code?2019 Community Moderator ElectionWere all Unix commands re-written in Linux?Are there still systems around with a /bin/sh binary?ip vs ifconfig commands pros and consSlightly confused about whether printf in the yash shell is a built-in command or notsu vs su - (on Debian): why is PATH the same?debian su - and su $PATH differences?Double square brackets for FreeBSDIs the GNU Coreutils copied from Unix?-c and -b options not working in mailx in ubuntuHow to compile and install programs from sourceWhere can I find the source code for `uptime`?How to create my own Linux distro (say from ubuntu source code)?Where to place source code for applications compiled from source?What is the difference between Unix, Linux, BSD and GNU?How to modify source code of collection of programs of a GNU/Linux OS?Why are there different types of linux distributions? What makes them unique, fundamentally?Source code of the patches for ShellshockMultibooting with LVMWhere can I find the source code specifically for the minimal debian installer cd?

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Do the common programs (for example: “ls”, “cat”) in Linux and BSD come from the same source code?



2019 Community Moderator ElectionWere all Unix commands re-written in Linux?Are there still systems around with a /bin/sh binary?ip vs ifconfig commands pros and consSlightly confused about whether printf in the yash shell is a built-in command or notsu vs su - (on Debian): why is PATH the same?debian su - and su $PATH differences?Double square brackets for FreeBSDIs the GNU Coreutils copied from Unix?-c and -b options not working in mailx in ubuntuHow to compile and install programs from sourceWhere can I find the source code for `uptime`?How to create my own Linux distro (say from ubuntu source code)?Where to place source code for applications compiled from source?What is the difference between Unix, Linux, BSD and GNU?How to modify source code of collection of programs of a GNU/Linux OS?Why are there different types of linux distributions? What makes them unique, fundamentally?Source code of the patches for ShellshockMultibooting with LVMWhere can I find the source code specifically for the minimal debian installer cd?










17















Both Linux and BSD have common programs like ls and cat and echo and kill.



Do they come from the same source code, or do both and Linux and BSD own their own unique source code for these programs?










share|improve this question









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user341875 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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  • 6





    Linux kernel itself doesn't have such code, it's just kernel. Depending on what kind of tool you use, these tools may or may not come from the same source code, fun fact is, they're usually not.

    – 炸鱼薯条德里克
    23 hours ago






  • 1





    Most tools have at least a BSD or Gnu heritage, then there are some originating from the Linux community or embedded projects (busybox). There are nearly no low level commands with a single implementation (but this is often the case for applications, related to naming rights)

    – eckes
    16 hours ago






  • 3





    Possible duplicate of Were all Unix commands re-written in Linux?

    – a CVn
    14 hours ago















17















Both Linux and BSD have common programs like ls and cat and echo and kill.



Do they come from the same source code, or do both and Linux and BSD own their own unique source code for these programs?










share|improve this question









New contributor




user341875 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.















  • 6





    Linux kernel itself doesn't have such code, it's just kernel. Depending on what kind of tool you use, these tools may or may not come from the same source code, fun fact is, they're usually not.

    – 炸鱼薯条德里克
    23 hours ago






  • 1





    Most tools have at least a BSD or Gnu heritage, then there are some originating from the Linux community or embedded projects (busybox). There are nearly no low level commands with a single implementation (but this is often the case for applications, related to naming rights)

    – eckes
    16 hours ago






  • 3





    Possible duplicate of Were all Unix commands re-written in Linux?

    – a CVn
    14 hours ago













17












17








17


4






Both Linux and BSD have common programs like ls and cat and echo and kill.



Do they come from the same source code, or do both and Linux and BSD own their own unique source code for these programs?










share|improve this question









New contributor




user341875 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.












Both Linux and BSD have common programs like ls and cat and echo and kill.



Do they come from the same source code, or do both and Linux and BSD own their own unique source code for these programs?







linux source bsd






share|improve this question









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user341875 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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share|improve this question









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share|improve this question




share|improve this question








edited 6 hours ago









Sergiy Kolodyazhnyy

10.6k42763




10.6k42763






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asked 23 hours ago









user341875user341875

893




893




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user341875 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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user341875 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







  • 6





    Linux kernel itself doesn't have such code, it's just kernel. Depending on what kind of tool you use, these tools may or may not come from the same source code, fun fact is, they're usually not.

    – 炸鱼薯条德里克
    23 hours ago






  • 1





    Most tools have at least a BSD or Gnu heritage, then there are some originating from the Linux community or embedded projects (busybox). There are nearly no low level commands with a single implementation (but this is often the case for applications, related to naming rights)

    – eckes
    16 hours ago






  • 3





    Possible duplicate of Were all Unix commands re-written in Linux?

    – a CVn
    14 hours ago












  • 6





    Linux kernel itself doesn't have such code, it's just kernel. Depending on what kind of tool you use, these tools may or may not come from the same source code, fun fact is, they're usually not.

    – 炸鱼薯条德里克
    23 hours ago






  • 1





    Most tools have at least a BSD or Gnu heritage, then there are some originating from the Linux community or embedded projects (busybox). There are nearly no low level commands with a single implementation (but this is often the case for applications, related to naming rights)

    – eckes
    16 hours ago






  • 3





    Possible duplicate of Were all Unix commands re-written in Linux?

    – a CVn
    14 hours ago







6




6





Linux kernel itself doesn't have such code, it's just kernel. Depending on what kind of tool you use, these tools may or may not come from the same source code, fun fact is, they're usually not.

– 炸鱼薯条德里克
23 hours ago





Linux kernel itself doesn't have such code, it's just kernel. Depending on what kind of tool you use, these tools may or may not come from the same source code, fun fact is, they're usually not.

– 炸鱼薯条德里克
23 hours ago




1




1





Most tools have at least a BSD or Gnu heritage, then there are some originating from the Linux community or embedded projects (busybox). There are nearly no low level commands with a single implementation (but this is often the case for applications, related to naming rights)

– eckes
16 hours ago





Most tools have at least a BSD or Gnu heritage, then there are some originating from the Linux community or embedded projects (busybox). There are nearly no low level commands with a single implementation (but this is often the case for applications, related to naming rights)

– eckes
16 hours ago




3




3





Possible duplicate of Were all Unix commands re-written in Linux?

– a CVn
14 hours ago





Possible duplicate of Were all Unix commands re-written in Linux?

– a CVn
14 hours ago










5 Answers
5






active

oldest

votes


















26














Linux is a kernel. It does not have the code for applications programs in the first place.



Linux-based operating systems do not even necessarily use the same source code as one another, let alone the same code as on the BSDs. There are famously multiple implementations of several fairly basic programs.



These include, but are not limited to:




  • ifconfig had 2 implementations, one in GNU inetutils and the other in NET-3 net-tools. It now has 3, the third being mine. (See https://unix.stackexchange.com/a/504084/5132.)


  • su has 2 implementations, one in util-linux and the other in shadow. Debian switched from one to the other in 2018, making several old questions and answers here on this WWW site wrong. (See https://unix.stackexchange.com/a/460769/5132 and, for one example, "su vs su - (on Debian): why is PATH the same?".)

  • There are seemingly umpteen (actually 4 on Debian/Ubuntu) possible places whence one can obtain the mailx command: GNU Mailutils, BSD mailx, NMH, and s-nail. (See https://unix.stackexchange.com/a/489510/5132.)

The BSDs are operating systems. They do contain the code for these programs. However, there is no single BSD operating system, and the code for such programs does sometimes vary amongst NetBSD, FreeBSD, OpenBSD, and DragonFly BSD. Moreover, it is definitely different to the code used for the several Linux-based operating systems.



Famously, Apple/NeXT used BSD applications softwares in MacOS/NeXTSTEP but enhanced several programs to support ACLs in ways different to the ways that the (other) BSDs did. One sets access controls using the chmod command, for example. So the Darwin versions of these commands are different yet again.



There are three added twists.



Programs like kill and echo are usually shell builtins. So the code for these commands varies according to what shell you are using, rather than what operating system.



Then there are BusyBox and ToyBox, available both for Linux-based operating systems and the BSDs and even used as the primary implementations of such commands on a few of the former, which have their own implementations of many commands.



Then there is OpenSolaris, from which come the likes of Illumos and Schillix, with the Solaris implementations of all of these tools, which is different yet again.



There are whole histories here, encompassing the original split between BSD and AT&T Unix, through the efforts to "PD" clone many Unix programs in the late 1980s and 1990s, around three decades of shuffling around after that, the whole open-source release of the code for Solaris, and OpenBSD's reimplementations of several things. Even the histories of tools that one might be misled into thinking have one implementation such as cron (which a lot of people erroneously think is the original Unix tool, or erroneously think is at least one single flavour written as "PD cron" by Paul Vixie in 1987, or do not realize has workalike replacements written by other people in the years since) are non-trivial.






share|improve this answer




















  • 2





    There's even PacBSD which is BSD user on Linux kernel...

    – Mehrdad
    17 hours ago











  • BSD was to my knowledged used in Mac OS X/NextStep because the license allowed them to use it with closed source software. NeXTStep included instructions for getting the source for the open source components. The same reasoning may have been used in Linux for providing a GPL userland with a GPL kernel.

    – Thorbjørn Ravn Andersen
    12 hours ago











  • Good answer, but it would benefit from a little explanation of the origins of the common Linux userlands.

    – Russell Borogove
    12 hours ago











  • That's really beyond the scope here, and should be a Q&A in its own right. We even have some such Q&As already. Consider unix.stackexchange.com/q/81302/5132 , for example. Q&As about the histories of the other toolsets would no doubt be welcome.

    – JdeBP
    12 hours ago












  • Programs like kill and echo are usually shell builtins, true, but there's of course /bin/ implementations for POSIX compliance, and those will vary by operating system. GNU stuff on Linux, BSD versions in BSDs and Mac OS X. I don't know what AIX or HPUX would use, but probably their own implementations. Good answer, +1

    – Sergiy Kolodyazhnyy
    6 hours ago


















5















Are these programs in Linux and BSD the same?




The short answer is: Not necessarily.



The source code of common programs such as ls, cat, echo, kill, etc. depend on what userland they come from. In other words, the userland your system uses. The most common userland used with the Linux kernel is GNU - hence the name GNU/Linux. Other userlands have been integrated with the Linux kernel, however.



The BSD's typically have their own userland that is developed separately from others like GNU. Even the BSD's themselves have different code bases. For example, both FreeBSD and OpenBSD have a "BSD userland", but their code base is different. If you look at their man pages (ps for example), they have different arguments that can be used.



One reason POSIX was developed was to address the issue of multiple code bases. If the common utilities delivered with a userland are POSIX compliant, you can assure that they will work (almost) the same whether they come from GNU, FreeBSD, OpenBSD, AIX, or other UNIX based systems.



As you probably know, the userlands listed above (except AIX) are open source. Feel free to poke around their code repositories and you will quickly see that they are not exactly the same.



Note: Even though GNU/Linux is the most popular, there have been attempts to use a GNU userland with FreeBSD/NetBSD kernels in the past. You can read more about them on wikipedia here.






share|improve this answer






























    4














    They have diffent sources, for example: https://github.com/freebsd/freebsd/blob/master/bin/kill/kill.c and https://github.com/karelzak/util-linux/blob/master/misc-utils/kill.c






    share|improve this answer






























      2














      First, I understand Linux as meaning GNU/Linux, which is the operating system, Linux is merely the kernel.



      Now, the source code is NOT the same. The GNU team created the utils, inspired by the UNIX tools that existed, and extended some of these.



      GNU kill and echo are shell built-ins in Bash, the default shell on most GNU systems, so they come with your shell, as in bash.



      ls, and cat are different, separate programs, inspired by UNIX ls and cat, respectively.



      There is a history of UNIX graph that explains where things come from, as you can see, GNU/Linux popped up without any direct ancestry.



      enter image description here



      Of the UNIX flavors, which relate to UNIX time sharing system, these commands all come from that, however, they could have been re-written multiple times.



      You can compare FreeBSD cat source code with GNU cat source code.



      Why do I not refer to GNU/Linux right through ? The waters are murky, you can install the GNU tools on the BSD's as well as on other UNIX systems, well, you can even install them on windows.



      Debian, of Debian GNU/Linux glory, on which Ubuntu and Mint are based (just two examples), offers a GNU distribution with a FreeBSD kernel: GNU/kFreeBSD



      Yes, the graph is outdated ...






      share|improve this answer

























      • I think this is the most comprehensive infographic on major *nixes I've seen thus far. +1 for that

        – Sergiy Kolodyazhnyy
        32 mins ago


















      0














      In addition to the above correct answers, you will find that the default shell on (almost?) every Linux distro is bash, while the default shell on at least OpenBSD and FreeBSD is not bash. It probably is csh, or ksh, but it is a couple of years since I used any BSD variant, so I am not absolutely sure. Anyway it never had the functionality of bash, even the way in which the previous command can be repeated was confusingly different. The difference in shells may change which of the simpler commands are shell built-ins and which are freestanding programs.



      With several distros now providing the GNU userland with an xBSD kernel, and potentially vice-versa, there is no one absolutely definitive answer to the question. The only absolutely foolproof way of knowing what you have on your system is to use your package manager to download the source and examine it, or examine it on-line if your distro has browseable source, although checking the license which applies would give a fairly good indication.






      share|improve this answer








      New contributor




      tiger99 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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      • Enjoy unix.stackexchange.com/q/322035/5132 , unix.stackexchange.com/q/193204/5132 , unix.stackexchange.com/q/496259/5132 , and many others here. And you'll stir up M. Chazelas if you claim that the C shell doesn't have the history expansion that the Bourne Again shell got from the C shell. (-:

        – JdeBP
        11 hours ago










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      5 Answers
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      5 Answers
      5






      active

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      active

      oldest

      votes






      active

      oldest

      votes









      26














      Linux is a kernel. It does not have the code for applications programs in the first place.



      Linux-based operating systems do not even necessarily use the same source code as one another, let alone the same code as on the BSDs. There are famously multiple implementations of several fairly basic programs.



      These include, but are not limited to:




      • ifconfig had 2 implementations, one in GNU inetutils and the other in NET-3 net-tools. It now has 3, the third being mine. (See https://unix.stackexchange.com/a/504084/5132.)


      • su has 2 implementations, one in util-linux and the other in shadow. Debian switched from one to the other in 2018, making several old questions and answers here on this WWW site wrong. (See https://unix.stackexchange.com/a/460769/5132 and, for one example, "su vs su - (on Debian): why is PATH the same?".)

      • There are seemingly umpteen (actually 4 on Debian/Ubuntu) possible places whence one can obtain the mailx command: GNU Mailutils, BSD mailx, NMH, and s-nail. (See https://unix.stackexchange.com/a/489510/5132.)

      The BSDs are operating systems. They do contain the code for these programs. However, there is no single BSD operating system, and the code for such programs does sometimes vary amongst NetBSD, FreeBSD, OpenBSD, and DragonFly BSD. Moreover, it is definitely different to the code used for the several Linux-based operating systems.



      Famously, Apple/NeXT used BSD applications softwares in MacOS/NeXTSTEP but enhanced several programs to support ACLs in ways different to the ways that the (other) BSDs did. One sets access controls using the chmod command, for example. So the Darwin versions of these commands are different yet again.



      There are three added twists.



      Programs like kill and echo are usually shell builtins. So the code for these commands varies according to what shell you are using, rather than what operating system.



      Then there are BusyBox and ToyBox, available both for Linux-based operating systems and the BSDs and even used as the primary implementations of such commands on a few of the former, which have their own implementations of many commands.



      Then there is OpenSolaris, from which come the likes of Illumos and Schillix, with the Solaris implementations of all of these tools, which is different yet again.



      There are whole histories here, encompassing the original split between BSD and AT&T Unix, through the efforts to "PD" clone many Unix programs in the late 1980s and 1990s, around three decades of shuffling around after that, the whole open-source release of the code for Solaris, and OpenBSD's reimplementations of several things. Even the histories of tools that one might be misled into thinking have one implementation such as cron (which a lot of people erroneously think is the original Unix tool, or erroneously think is at least one single flavour written as "PD cron" by Paul Vixie in 1987, or do not realize has workalike replacements written by other people in the years since) are non-trivial.






      share|improve this answer




















      • 2





        There's even PacBSD which is BSD user on Linux kernel...

        – Mehrdad
        17 hours ago











      • BSD was to my knowledged used in Mac OS X/NextStep because the license allowed them to use it with closed source software. NeXTStep included instructions for getting the source for the open source components. The same reasoning may have been used in Linux for providing a GPL userland with a GPL kernel.

        – Thorbjørn Ravn Andersen
        12 hours ago











      • Good answer, but it would benefit from a little explanation of the origins of the common Linux userlands.

        – Russell Borogove
        12 hours ago











      • That's really beyond the scope here, and should be a Q&A in its own right. We even have some such Q&As already. Consider unix.stackexchange.com/q/81302/5132 , for example. Q&As about the histories of the other toolsets would no doubt be welcome.

        – JdeBP
        12 hours ago












      • Programs like kill and echo are usually shell builtins, true, but there's of course /bin/ implementations for POSIX compliance, and those will vary by operating system. GNU stuff on Linux, BSD versions in BSDs and Mac OS X. I don't know what AIX or HPUX would use, but probably their own implementations. Good answer, +1

        – Sergiy Kolodyazhnyy
        6 hours ago















      26














      Linux is a kernel. It does not have the code for applications programs in the first place.



      Linux-based operating systems do not even necessarily use the same source code as one another, let alone the same code as on the BSDs. There are famously multiple implementations of several fairly basic programs.



      These include, but are not limited to:




      • ifconfig had 2 implementations, one in GNU inetutils and the other in NET-3 net-tools. It now has 3, the third being mine. (See https://unix.stackexchange.com/a/504084/5132.)


      • su has 2 implementations, one in util-linux and the other in shadow. Debian switched from one to the other in 2018, making several old questions and answers here on this WWW site wrong. (See https://unix.stackexchange.com/a/460769/5132 and, for one example, "su vs su - (on Debian): why is PATH the same?".)

      • There are seemingly umpteen (actually 4 on Debian/Ubuntu) possible places whence one can obtain the mailx command: GNU Mailutils, BSD mailx, NMH, and s-nail. (See https://unix.stackexchange.com/a/489510/5132.)

      The BSDs are operating systems. They do contain the code for these programs. However, there is no single BSD operating system, and the code for such programs does sometimes vary amongst NetBSD, FreeBSD, OpenBSD, and DragonFly BSD. Moreover, it is definitely different to the code used for the several Linux-based operating systems.



      Famously, Apple/NeXT used BSD applications softwares in MacOS/NeXTSTEP but enhanced several programs to support ACLs in ways different to the ways that the (other) BSDs did. One sets access controls using the chmod command, for example. So the Darwin versions of these commands are different yet again.



      There are three added twists.



      Programs like kill and echo are usually shell builtins. So the code for these commands varies according to what shell you are using, rather than what operating system.



      Then there are BusyBox and ToyBox, available both for Linux-based operating systems and the BSDs and even used as the primary implementations of such commands on a few of the former, which have their own implementations of many commands.



      Then there is OpenSolaris, from which come the likes of Illumos and Schillix, with the Solaris implementations of all of these tools, which is different yet again.



      There are whole histories here, encompassing the original split between BSD and AT&T Unix, through the efforts to "PD" clone many Unix programs in the late 1980s and 1990s, around three decades of shuffling around after that, the whole open-source release of the code for Solaris, and OpenBSD's reimplementations of several things. Even the histories of tools that one might be misled into thinking have one implementation such as cron (which a lot of people erroneously think is the original Unix tool, or erroneously think is at least one single flavour written as "PD cron" by Paul Vixie in 1987, or do not realize has workalike replacements written by other people in the years since) are non-trivial.






      share|improve this answer




















      • 2





        There's even PacBSD which is BSD user on Linux kernel...

        – Mehrdad
        17 hours ago











      • BSD was to my knowledged used in Mac OS X/NextStep because the license allowed them to use it with closed source software. NeXTStep included instructions for getting the source for the open source components. The same reasoning may have been used in Linux for providing a GPL userland with a GPL kernel.

        – Thorbjørn Ravn Andersen
        12 hours ago











      • Good answer, but it would benefit from a little explanation of the origins of the common Linux userlands.

        – Russell Borogove
        12 hours ago











      • That's really beyond the scope here, and should be a Q&A in its own right. We even have some such Q&As already. Consider unix.stackexchange.com/q/81302/5132 , for example. Q&As about the histories of the other toolsets would no doubt be welcome.

        – JdeBP
        12 hours ago












      • Programs like kill and echo are usually shell builtins, true, but there's of course /bin/ implementations for POSIX compliance, and those will vary by operating system. GNU stuff on Linux, BSD versions in BSDs and Mac OS X. I don't know what AIX or HPUX would use, but probably their own implementations. Good answer, +1

        – Sergiy Kolodyazhnyy
        6 hours ago













      26












      26








      26







      Linux is a kernel. It does not have the code for applications programs in the first place.



      Linux-based operating systems do not even necessarily use the same source code as one another, let alone the same code as on the BSDs. There are famously multiple implementations of several fairly basic programs.



      These include, but are not limited to:




      • ifconfig had 2 implementations, one in GNU inetutils and the other in NET-3 net-tools. It now has 3, the third being mine. (See https://unix.stackexchange.com/a/504084/5132.)


      • su has 2 implementations, one in util-linux and the other in shadow. Debian switched from one to the other in 2018, making several old questions and answers here on this WWW site wrong. (See https://unix.stackexchange.com/a/460769/5132 and, for one example, "su vs su - (on Debian): why is PATH the same?".)

      • There are seemingly umpteen (actually 4 on Debian/Ubuntu) possible places whence one can obtain the mailx command: GNU Mailutils, BSD mailx, NMH, and s-nail. (See https://unix.stackexchange.com/a/489510/5132.)

      The BSDs are operating systems. They do contain the code for these programs. However, there is no single BSD operating system, and the code for such programs does sometimes vary amongst NetBSD, FreeBSD, OpenBSD, and DragonFly BSD. Moreover, it is definitely different to the code used for the several Linux-based operating systems.



      Famously, Apple/NeXT used BSD applications softwares in MacOS/NeXTSTEP but enhanced several programs to support ACLs in ways different to the ways that the (other) BSDs did. One sets access controls using the chmod command, for example. So the Darwin versions of these commands are different yet again.



      There are three added twists.



      Programs like kill and echo are usually shell builtins. So the code for these commands varies according to what shell you are using, rather than what operating system.



      Then there are BusyBox and ToyBox, available both for Linux-based operating systems and the BSDs and even used as the primary implementations of such commands on a few of the former, which have their own implementations of many commands.



      Then there is OpenSolaris, from which come the likes of Illumos and Schillix, with the Solaris implementations of all of these tools, which is different yet again.



      There are whole histories here, encompassing the original split between BSD and AT&T Unix, through the efforts to "PD" clone many Unix programs in the late 1980s and 1990s, around three decades of shuffling around after that, the whole open-source release of the code for Solaris, and OpenBSD's reimplementations of several things. Even the histories of tools that one might be misled into thinking have one implementation such as cron (which a lot of people erroneously think is the original Unix tool, or erroneously think is at least one single flavour written as "PD cron" by Paul Vixie in 1987, or do not realize has workalike replacements written by other people in the years since) are non-trivial.






      share|improve this answer















      Linux is a kernel. It does not have the code for applications programs in the first place.



      Linux-based operating systems do not even necessarily use the same source code as one another, let alone the same code as on the BSDs. There are famously multiple implementations of several fairly basic programs.



      These include, but are not limited to:




      • ifconfig had 2 implementations, one in GNU inetutils and the other in NET-3 net-tools. It now has 3, the third being mine. (See https://unix.stackexchange.com/a/504084/5132.)


      • su has 2 implementations, one in util-linux and the other in shadow. Debian switched from one to the other in 2018, making several old questions and answers here on this WWW site wrong. (See https://unix.stackexchange.com/a/460769/5132 and, for one example, "su vs su - (on Debian): why is PATH the same?".)

      • There are seemingly umpteen (actually 4 on Debian/Ubuntu) possible places whence one can obtain the mailx command: GNU Mailutils, BSD mailx, NMH, and s-nail. (See https://unix.stackexchange.com/a/489510/5132.)

      The BSDs are operating systems. They do contain the code for these programs. However, there is no single BSD operating system, and the code for such programs does sometimes vary amongst NetBSD, FreeBSD, OpenBSD, and DragonFly BSD. Moreover, it is definitely different to the code used for the several Linux-based operating systems.



      Famously, Apple/NeXT used BSD applications softwares in MacOS/NeXTSTEP but enhanced several programs to support ACLs in ways different to the ways that the (other) BSDs did. One sets access controls using the chmod command, for example. So the Darwin versions of these commands are different yet again.



      There are three added twists.



      Programs like kill and echo are usually shell builtins. So the code for these commands varies according to what shell you are using, rather than what operating system.



      Then there are BusyBox and ToyBox, available both for Linux-based operating systems and the BSDs and even used as the primary implementations of such commands on a few of the former, which have their own implementations of many commands.



      Then there is OpenSolaris, from which come the likes of Illumos and Schillix, with the Solaris implementations of all of these tools, which is different yet again.



      There are whole histories here, encompassing the original split between BSD and AT&T Unix, through the efforts to "PD" clone many Unix programs in the late 1980s and 1990s, around three decades of shuffling around after that, the whole open-source release of the code for Solaris, and OpenBSD's reimplementations of several things. Even the histories of tools that one might be misled into thinking have one implementation such as cron (which a lot of people erroneously think is the original Unix tool, or erroneously think is at least one single flavour written as "PD cron" by Paul Vixie in 1987, or do not realize has workalike replacements written by other people in the years since) are non-trivial.







      share|improve this answer














      share|improve this answer



      share|improve this answer








      edited 15 hours ago

























      answered 19 hours ago









      JdeBPJdeBP

      36.8k475176




      36.8k475176







      • 2





        There's even PacBSD which is BSD user on Linux kernel...

        – Mehrdad
        17 hours ago











      • BSD was to my knowledged used in Mac OS X/NextStep because the license allowed them to use it with closed source software. NeXTStep included instructions for getting the source for the open source components. The same reasoning may have been used in Linux for providing a GPL userland with a GPL kernel.

        – Thorbjørn Ravn Andersen
        12 hours ago











      • Good answer, but it would benefit from a little explanation of the origins of the common Linux userlands.

        – Russell Borogove
        12 hours ago











      • That's really beyond the scope here, and should be a Q&A in its own right. We even have some such Q&As already. Consider unix.stackexchange.com/q/81302/5132 , for example. Q&As about the histories of the other toolsets would no doubt be welcome.

        – JdeBP
        12 hours ago












      • Programs like kill and echo are usually shell builtins, true, but there's of course /bin/ implementations for POSIX compliance, and those will vary by operating system. GNU stuff on Linux, BSD versions in BSDs and Mac OS X. I don't know what AIX or HPUX would use, but probably their own implementations. Good answer, +1

        – Sergiy Kolodyazhnyy
        6 hours ago












      • 2





        There's even PacBSD which is BSD user on Linux kernel...

        – Mehrdad
        17 hours ago











      • BSD was to my knowledged used in Mac OS X/NextStep because the license allowed them to use it with closed source software. NeXTStep included instructions for getting the source for the open source components. The same reasoning may have been used in Linux for providing a GPL userland with a GPL kernel.

        – Thorbjørn Ravn Andersen
        12 hours ago











      • Good answer, but it would benefit from a little explanation of the origins of the common Linux userlands.

        – Russell Borogove
        12 hours ago











      • That's really beyond the scope here, and should be a Q&A in its own right. We even have some such Q&As already. Consider unix.stackexchange.com/q/81302/5132 , for example. Q&As about the histories of the other toolsets would no doubt be welcome.

        – JdeBP
        12 hours ago












      • Programs like kill and echo are usually shell builtins, true, but there's of course /bin/ implementations for POSIX compliance, and those will vary by operating system. GNU stuff on Linux, BSD versions in BSDs and Mac OS X. I don't know what AIX or HPUX would use, but probably their own implementations. Good answer, +1

        – Sergiy Kolodyazhnyy
        6 hours ago







      2




      2





      There's even PacBSD which is BSD user on Linux kernel...

      – Mehrdad
      17 hours ago





      There's even PacBSD which is BSD user on Linux kernel...

      – Mehrdad
      17 hours ago













      BSD was to my knowledged used in Mac OS X/NextStep because the license allowed them to use it with closed source software. NeXTStep included instructions for getting the source for the open source components. The same reasoning may have been used in Linux for providing a GPL userland with a GPL kernel.

      – Thorbjørn Ravn Andersen
      12 hours ago





      BSD was to my knowledged used in Mac OS X/NextStep because the license allowed them to use it with closed source software. NeXTStep included instructions for getting the source for the open source components. The same reasoning may have been used in Linux for providing a GPL userland with a GPL kernel.

      – Thorbjørn Ravn Andersen
      12 hours ago













      Good answer, but it would benefit from a little explanation of the origins of the common Linux userlands.

      – Russell Borogove
      12 hours ago





      Good answer, but it would benefit from a little explanation of the origins of the common Linux userlands.

      – Russell Borogove
      12 hours ago













      That's really beyond the scope here, and should be a Q&A in its own right. We even have some such Q&As already. Consider unix.stackexchange.com/q/81302/5132 , for example. Q&As about the histories of the other toolsets would no doubt be welcome.

      – JdeBP
      12 hours ago






      That's really beyond the scope here, and should be a Q&A in its own right. We even have some such Q&As already. Consider unix.stackexchange.com/q/81302/5132 , for example. Q&As about the histories of the other toolsets would no doubt be welcome.

      – JdeBP
      12 hours ago














      Programs like kill and echo are usually shell builtins, true, but there's of course /bin/ implementations for POSIX compliance, and those will vary by operating system. GNU stuff on Linux, BSD versions in BSDs and Mac OS X. I don't know what AIX or HPUX would use, but probably their own implementations. Good answer, +1

      – Sergiy Kolodyazhnyy
      6 hours ago





      Programs like kill and echo are usually shell builtins, true, but there's of course /bin/ implementations for POSIX compliance, and those will vary by operating system. GNU stuff on Linux, BSD versions in BSDs and Mac OS X. I don't know what AIX or HPUX would use, but probably their own implementations. Good answer, +1

      – Sergiy Kolodyazhnyy
      6 hours ago













      5















      Are these programs in Linux and BSD the same?




      The short answer is: Not necessarily.



      The source code of common programs such as ls, cat, echo, kill, etc. depend on what userland they come from. In other words, the userland your system uses. The most common userland used with the Linux kernel is GNU - hence the name GNU/Linux. Other userlands have been integrated with the Linux kernel, however.



      The BSD's typically have their own userland that is developed separately from others like GNU. Even the BSD's themselves have different code bases. For example, both FreeBSD and OpenBSD have a "BSD userland", but their code base is different. If you look at their man pages (ps for example), they have different arguments that can be used.



      One reason POSIX was developed was to address the issue of multiple code bases. If the common utilities delivered with a userland are POSIX compliant, you can assure that they will work (almost) the same whether they come from GNU, FreeBSD, OpenBSD, AIX, or other UNIX based systems.



      As you probably know, the userlands listed above (except AIX) are open source. Feel free to poke around their code repositories and you will quickly see that they are not exactly the same.



      Note: Even though GNU/Linux is the most popular, there have been attempts to use a GNU userland with FreeBSD/NetBSD kernels in the past. You can read more about them on wikipedia here.






      share|improve this answer



























        5















        Are these programs in Linux and BSD the same?




        The short answer is: Not necessarily.



        The source code of common programs such as ls, cat, echo, kill, etc. depend on what userland they come from. In other words, the userland your system uses. The most common userland used with the Linux kernel is GNU - hence the name GNU/Linux. Other userlands have been integrated with the Linux kernel, however.



        The BSD's typically have their own userland that is developed separately from others like GNU. Even the BSD's themselves have different code bases. For example, both FreeBSD and OpenBSD have a "BSD userland", but their code base is different. If you look at their man pages (ps for example), they have different arguments that can be used.



        One reason POSIX was developed was to address the issue of multiple code bases. If the common utilities delivered with a userland are POSIX compliant, you can assure that they will work (almost) the same whether they come from GNU, FreeBSD, OpenBSD, AIX, or other UNIX based systems.



        As you probably know, the userlands listed above (except AIX) are open source. Feel free to poke around their code repositories and you will quickly see that they are not exactly the same.



        Note: Even though GNU/Linux is the most popular, there have been attempts to use a GNU userland with FreeBSD/NetBSD kernels in the past. You can read more about them on wikipedia here.






        share|improve this answer

























          5












          5








          5








          Are these programs in Linux and BSD the same?




          The short answer is: Not necessarily.



          The source code of common programs such as ls, cat, echo, kill, etc. depend on what userland they come from. In other words, the userland your system uses. The most common userland used with the Linux kernel is GNU - hence the name GNU/Linux. Other userlands have been integrated with the Linux kernel, however.



          The BSD's typically have their own userland that is developed separately from others like GNU. Even the BSD's themselves have different code bases. For example, both FreeBSD and OpenBSD have a "BSD userland", but their code base is different. If you look at their man pages (ps for example), they have different arguments that can be used.



          One reason POSIX was developed was to address the issue of multiple code bases. If the common utilities delivered with a userland are POSIX compliant, you can assure that they will work (almost) the same whether they come from GNU, FreeBSD, OpenBSD, AIX, or other UNIX based systems.



          As you probably know, the userlands listed above (except AIX) are open source. Feel free to poke around their code repositories and you will quickly see that they are not exactly the same.



          Note: Even though GNU/Linux is the most popular, there have been attempts to use a GNU userland with FreeBSD/NetBSD kernels in the past. You can read more about them on wikipedia here.






          share|improve this answer














          Are these programs in Linux and BSD the same?




          The short answer is: Not necessarily.



          The source code of common programs such as ls, cat, echo, kill, etc. depend on what userland they come from. In other words, the userland your system uses. The most common userland used with the Linux kernel is GNU - hence the name GNU/Linux. Other userlands have been integrated with the Linux kernel, however.



          The BSD's typically have their own userland that is developed separately from others like GNU. Even the BSD's themselves have different code bases. For example, both FreeBSD and OpenBSD have a "BSD userland", but their code base is different. If you look at their man pages (ps for example), they have different arguments that can be used.



          One reason POSIX was developed was to address the issue of multiple code bases. If the common utilities delivered with a userland are POSIX compliant, you can assure that they will work (almost) the same whether they come from GNU, FreeBSD, OpenBSD, AIX, or other UNIX based systems.



          As you probably know, the userlands listed above (except AIX) are open source. Feel free to poke around their code repositories and you will quickly see that they are not exactly the same.



          Note: Even though GNU/Linux is the most popular, there have been attempts to use a GNU userland with FreeBSD/NetBSD kernels in the past. You can read more about them on wikipedia here.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered 19 hours ago









          PeschkePeschke

          2,676925




          2,676925





















              4














              They have diffent sources, for example: https://github.com/freebsd/freebsd/blob/master/bin/kill/kill.c and https://github.com/karelzak/util-linux/blob/master/misc-utils/kill.c






              share|improve this answer



























                4














                They have diffent sources, for example: https://github.com/freebsd/freebsd/blob/master/bin/kill/kill.c and https://github.com/karelzak/util-linux/blob/master/misc-utils/kill.c






                share|improve this answer

























                  4












                  4








                  4







                  They have diffent sources, for example: https://github.com/freebsd/freebsd/blob/master/bin/kill/kill.c and https://github.com/karelzak/util-linux/blob/master/misc-utils/kill.c






                  share|improve this answer













                  They have diffent sources, for example: https://github.com/freebsd/freebsd/blob/master/bin/kill/kill.c and https://github.com/karelzak/util-linux/blob/master/misc-utils/kill.c







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered 23 hours ago









                  Fedor DikarevFedor Dikarev

                  1,063310




                  1,063310





















                      2














                      First, I understand Linux as meaning GNU/Linux, which is the operating system, Linux is merely the kernel.



                      Now, the source code is NOT the same. The GNU team created the utils, inspired by the UNIX tools that existed, and extended some of these.



                      GNU kill and echo are shell built-ins in Bash, the default shell on most GNU systems, so they come with your shell, as in bash.



                      ls, and cat are different, separate programs, inspired by UNIX ls and cat, respectively.



                      There is a history of UNIX graph that explains where things come from, as you can see, GNU/Linux popped up without any direct ancestry.



                      enter image description here



                      Of the UNIX flavors, which relate to UNIX time sharing system, these commands all come from that, however, they could have been re-written multiple times.



                      You can compare FreeBSD cat source code with GNU cat source code.



                      Why do I not refer to GNU/Linux right through ? The waters are murky, you can install the GNU tools on the BSD's as well as on other UNIX systems, well, you can even install them on windows.



                      Debian, of Debian GNU/Linux glory, on which Ubuntu and Mint are based (just two examples), offers a GNU distribution with a FreeBSD kernel: GNU/kFreeBSD



                      Yes, the graph is outdated ...






                      share|improve this answer

























                      • I think this is the most comprehensive infographic on major *nixes I've seen thus far. +1 for that

                        – Sergiy Kolodyazhnyy
                        32 mins ago















                      2














                      First, I understand Linux as meaning GNU/Linux, which is the operating system, Linux is merely the kernel.



                      Now, the source code is NOT the same. The GNU team created the utils, inspired by the UNIX tools that existed, and extended some of these.



                      GNU kill and echo are shell built-ins in Bash, the default shell on most GNU systems, so they come with your shell, as in bash.



                      ls, and cat are different, separate programs, inspired by UNIX ls and cat, respectively.



                      There is a history of UNIX graph that explains where things come from, as you can see, GNU/Linux popped up without any direct ancestry.



                      enter image description here



                      Of the UNIX flavors, which relate to UNIX time sharing system, these commands all come from that, however, they could have been re-written multiple times.



                      You can compare FreeBSD cat source code with GNU cat source code.



                      Why do I not refer to GNU/Linux right through ? The waters are murky, you can install the GNU tools on the BSD's as well as on other UNIX systems, well, you can even install them on windows.



                      Debian, of Debian GNU/Linux glory, on which Ubuntu and Mint are based (just two examples), offers a GNU distribution with a FreeBSD kernel: GNU/kFreeBSD



                      Yes, the graph is outdated ...






                      share|improve this answer

























                      • I think this is the most comprehensive infographic on major *nixes I've seen thus far. +1 for that

                        – Sergiy Kolodyazhnyy
                        32 mins ago













                      2












                      2








                      2







                      First, I understand Linux as meaning GNU/Linux, which is the operating system, Linux is merely the kernel.



                      Now, the source code is NOT the same. The GNU team created the utils, inspired by the UNIX tools that existed, and extended some of these.



                      GNU kill and echo are shell built-ins in Bash, the default shell on most GNU systems, so they come with your shell, as in bash.



                      ls, and cat are different, separate programs, inspired by UNIX ls and cat, respectively.



                      There is a history of UNIX graph that explains where things come from, as you can see, GNU/Linux popped up without any direct ancestry.



                      enter image description here



                      Of the UNIX flavors, which relate to UNIX time sharing system, these commands all come from that, however, they could have been re-written multiple times.



                      You can compare FreeBSD cat source code with GNU cat source code.



                      Why do I not refer to GNU/Linux right through ? The waters are murky, you can install the GNU tools on the BSD's as well as on other UNIX systems, well, you can even install them on windows.



                      Debian, of Debian GNU/Linux glory, on which Ubuntu and Mint are based (just two examples), offers a GNU distribution with a FreeBSD kernel: GNU/kFreeBSD



                      Yes, the graph is outdated ...






                      share|improve this answer















                      First, I understand Linux as meaning GNU/Linux, which is the operating system, Linux is merely the kernel.



                      Now, the source code is NOT the same. The GNU team created the utils, inspired by the UNIX tools that existed, and extended some of these.



                      GNU kill and echo are shell built-ins in Bash, the default shell on most GNU systems, so they come with your shell, as in bash.



                      ls, and cat are different, separate programs, inspired by UNIX ls and cat, respectively.



                      There is a history of UNIX graph that explains where things come from, as you can see, GNU/Linux popped up without any direct ancestry.



                      enter image description here



                      Of the UNIX flavors, which relate to UNIX time sharing system, these commands all come from that, however, they could have been re-written multiple times.



                      You can compare FreeBSD cat source code with GNU cat source code.



                      Why do I not refer to GNU/Linux right through ? The waters are murky, you can install the GNU tools on the BSD's as well as on other UNIX systems, well, you can even install them on windows.



                      Debian, of Debian GNU/Linux glory, on which Ubuntu and Mint are based (just two examples), offers a GNU distribution with a FreeBSD kernel: GNU/kFreeBSD



                      Yes, the graph is outdated ...







                      share|improve this answer














                      share|improve this answer



                      share|improve this answer








                      edited 16 hours ago

























                      answered 17 hours ago









                      thecarpythecarpy

                      2,390825




                      2,390825












                      • I think this is the most comprehensive infographic on major *nixes I've seen thus far. +1 for that

                        – Sergiy Kolodyazhnyy
                        32 mins ago

















                      • I think this is the most comprehensive infographic on major *nixes I've seen thus far. +1 for that

                        – Sergiy Kolodyazhnyy
                        32 mins ago
















                      I think this is the most comprehensive infographic on major *nixes I've seen thus far. +1 for that

                      – Sergiy Kolodyazhnyy
                      32 mins ago





                      I think this is the most comprehensive infographic on major *nixes I've seen thus far. +1 for that

                      – Sergiy Kolodyazhnyy
                      32 mins ago











                      0














                      In addition to the above correct answers, you will find that the default shell on (almost?) every Linux distro is bash, while the default shell on at least OpenBSD and FreeBSD is not bash. It probably is csh, or ksh, but it is a couple of years since I used any BSD variant, so I am not absolutely sure. Anyway it never had the functionality of bash, even the way in which the previous command can be repeated was confusingly different. The difference in shells may change which of the simpler commands are shell built-ins and which are freestanding programs.



                      With several distros now providing the GNU userland with an xBSD kernel, and potentially vice-versa, there is no one absolutely definitive answer to the question. The only absolutely foolproof way of knowing what you have on your system is to use your package manager to download the source and examine it, or examine it on-line if your distro has browseable source, although checking the license which applies would give a fairly good indication.






                      share|improve this answer








                      New contributor




                      tiger99 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                      Check out our Code of Conduct.




















                      • Enjoy unix.stackexchange.com/q/322035/5132 , unix.stackexchange.com/q/193204/5132 , unix.stackexchange.com/q/496259/5132 , and many others here. And you'll stir up M. Chazelas if you claim that the C shell doesn't have the history expansion that the Bourne Again shell got from the C shell. (-:

                        – JdeBP
                        11 hours ago















                      0














                      In addition to the above correct answers, you will find that the default shell on (almost?) every Linux distro is bash, while the default shell on at least OpenBSD and FreeBSD is not bash. It probably is csh, or ksh, but it is a couple of years since I used any BSD variant, so I am not absolutely sure. Anyway it never had the functionality of bash, even the way in which the previous command can be repeated was confusingly different. The difference in shells may change which of the simpler commands are shell built-ins and which are freestanding programs.



                      With several distros now providing the GNU userland with an xBSD kernel, and potentially vice-versa, there is no one absolutely definitive answer to the question. The only absolutely foolproof way of knowing what you have on your system is to use your package manager to download the source and examine it, or examine it on-line if your distro has browseable source, although checking the license which applies would give a fairly good indication.






                      share|improve this answer








                      New contributor




                      tiger99 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                      Check out our Code of Conduct.




















                      • Enjoy unix.stackexchange.com/q/322035/5132 , unix.stackexchange.com/q/193204/5132 , unix.stackexchange.com/q/496259/5132 , and many others here. And you'll stir up M. Chazelas if you claim that the C shell doesn't have the history expansion that the Bourne Again shell got from the C shell. (-:

                        – JdeBP
                        11 hours ago













                      0












                      0








                      0







                      In addition to the above correct answers, you will find that the default shell on (almost?) every Linux distro is bash, while the default shell on at least OpenBSD and FreeBSD is not bash. It probably is csh, or ksh, but it is a couple of years since I used any BSD variant, so I am not absolutely sure. Anyway it never had the functionality of bash, even the way in which the previous command can be repeated was confusingly different. The difference in shells may change which of the simpler commands are shell built-ins and which are freestanding programs.



                      With several distros now providing the GNU userland with an xBSD kernel, and potentially vice-versa, there is no one absolutely definitive answer to the question. The only absolutely foolproof way of knowing what you have on your system is to use your package manager to download the source and examine it, or examine it on-line if your distro has browseable source, although checking the license which applies would give a fairly good indication.






                      share|improve this answer








                      New contributor




                      tiger99 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                      Check out our Code of Conduct.










                      In addition to the above correct answers, you will find that the default shell on (almost?) every Linux distro is bash, while the default shell on at least OpenBSD and FreeBSD is not bash. It probably is csh, or ksh, but it is a couple of years since I used any BSD variant, so I am not absolutely sure. Anyway it never had the functionality of bash, even the way in which the previous command can be repeated was confusingly different. The difference in shells may change which of the simpler commands are shell built-ins and which are freestanding programs.



                      With several distros now providing the GNU userland with an xBSD kernel, and potentially vice-versa, there is no one absolutely definitive answer to the question. The only absolutely foolproof way of knowing what you have on your system is to use your package manager to download the source and examine it, or examine it on-line if your distro has browseable source, although checking the license which applies would give a fairly good indication.







                      share|improve this answer








                      New contributor




                      tiger99 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                      Check out our Code of Conduct.









                      share|improve this answer



                      share|improve this answer






                      New contributor




                      tiger99 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                      Check out our Code of Conduct.









                      answered 12 hours ago









                      tiger99tiger99

                      1




                      1




                      New contributor




                      tiger99 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                      Check out our Code of Conduct.





                      New contributor





                      tiger99 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                      Check out our Code of Conduct.






                      tiger99 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
                      Check out our Code of Conduct.












                      • Enjoy unix.stackexchange.com/q/322035/5132 , unix.stackexchange.com/q/193204/5132 , unix.stackexchange.com/q/496259/5132 , and many others here. And you'll stir up M. Chazelas if you claim that the C shell doesn't have the history expansion that the Bourne Again shell got from the C shell. (-:

                        – JdeBP
                        11 hours ago

















                      • Enjoy unix.stackexchange.com/q/322035/5132 , unix.stackexchange.com/q/193204/5132 , unix.stackexchange.com/q/496259/5132 , and many others here. And you'll stir up M. Chazelas if you claim that the C shell doesn't have the history expansion that the Bourne Again shell got from the C shell. (-:

                        – JdeBP
                        11 hours ago
















                      Enjoy unix.stackexchange.com/q/322035/5132 , unix.stackexchange.com/q/193204/5132 , unix.stackexchange.com/q/496259/5132 , and many others here. And you'll stir up M. Chazelas if you claim that the C shell doesn't have the history expansion that the Bourne Again shell got from the C shell. (-:

                      – JdeBP
                      11 hours ago





                      Enjoy unix.stackexchange.com/q/322035/5132 , unix.stackexchange.com/q/193204/5132 , unix.stackexchange.com/q/496259/5132 , and many others here. And you'll stir up M. Chazelas if you claim that the C shell doesn't have the history expansion that the Bourne Again shell got from the C shell. (-:

                      – JdeBP
                      11 hours ago










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