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Scripts using #!/bin/sh instead of #!/usr/bin/env (ba)sh won't use your shiny new shell. Including scripts deep inside the build system of misc. software that y

Scripts using #!/bin/sh instead of #!/usr/bin/env (ba)sh won't use your shiny new shell. Including scripts deep inside the build system of misc. software that you won't modify. The only way is to set their strange /etc/private symlink (cf sh(1)) to change what /bin/sh execs, and to do it again after each update which resets it.

vorakl 2y ago
I wonder what is the origin of this "/bin/sh" and why it's often assumed that sh is in /bin by default. The standard is pretty clear about that: "Applications should note that the standard PATH to the shell cannot be assumed to be either /bin/sh or /usr/bin/sh, and should be determined by interrogation of the PATH returned by getconf PATH, ensuring that the returned pathname is an absolute pathname and not a shell built-in." "Furthermore, on systems that support executable scripts (the "#!" construct), it is recommended that applications using executable scripts install them using getconf PATH to determine the shell pathname and update the "#!" script appropriately as it is being installed (for example, with sed)." Ref: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/sh.html https://pubs.opengroup.org/onlinepubs/9699919799/utilities/s... So, apparently on systems, where sh resides in /bin, "getconf CONF" will return /bin . However, this is not always the case. For example, on my Fedora Linux it is /usr/bin $ getconf PATH /usr/bin $ ls -l /usr/bin/sh lrwxrwxrwx. 1 root root 4 Jan 2 2023 /usr/bin/sh -> bash $ ls -l /bin/sh lrwxrwxrwx. 1 root root 4 Jan 2 2023 /bin/sh -> bash $ ls -ld /bin lrwxrwxrwx. 1 root root 7 Aug 9 2022 /bin -> usr/bin
- BoingBoomTschak 2y ago
  Probably the natural consequence of shebang limitations and the "chicken and egg problem" of env(1) that isn't always in /usr/bin. If only we could write #!sh to do a PATH lookup... Thanks for finding the exact POSIX section describing its own failings! On Gentoo (with the recent merged-usr profile), getconf PATH returns "/bin:/usr/bin", heh.

vorakl 2y ago

I wonder what is the origin of this "/bin/sh" and why it's often assumed that sh is in /bin by default. The standard is pretty clear about that: "Applications should note that the standard PATH to the shell cannot be assumed to be either /bin/sh or /usr/bin/sh, and should be determined by interrogation of the PATH returned by getconf PATH, ensuring that the returned pathname is an absolute pathname and not a shell built-in." "Furthermore, on systems that support executable scripts (the "#!" construct), it is recommended that applications using executable scripts install them using getconf PATH to determine the shell pathname and update the "#!" script appropriately as it is being installed (for example, with sed)." Ref: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/sh.html https://pubs.opengroup.org/onlinepubs/9699919799/utilities/s... So, apparently on systems, where sh resides in /bin, "getconf CONF" will return /bin . However, this is not always the case. For example, on my Fedora Linux it is /usr/bin $ getconf PATH /usr/bin $ ls -l /usr/bin/sh lrwxrwxrwx. 1 root root 4 Jan 2 2023 /usr/bin/sh -> bash $ ls -l /bin/sh lrwxrwxrwx. 1 root root 4 Jan 2 2023 /bin/sh -> bash $ ls -ld /bin lrwxrwxrwx. 1 root root 7 Aug 9 2022 /bin -> usr/bin

BoingBoomTschak 2y ago
Probably the natural consequence of shebang limitations and the "chicken and egg problem" of env(1) that isn't always in /usr/bin. If only we could write #!sh to do a PATH lookup... Thanks for finding the exact POSIX section describing its own failings! On Gentoo (with the recent merged-usr profile), getconf PATH returns "/bin:/usr/bin", heh.