4 ms·

I don't quite get the recommendation to always use env bash over #!/bin/bash? If I use the full path, it is to get just that - the system's Bash. If it is missi

by jbrnh 7y ago

I don't quite get the recommendation to always use env bash over #!/bin/bash? If I use the full path, it is to get just that - the system's Bash. If it is missing or overruled in $PATH then I most likely don't want the script to run in the first place.

YawningAngel 7y ago
'System bash' isn't a universal or clear concept. For example, if you're using Modern OS X, you likely have bash via brew or some other userspace package manager but no system bash. Presumably you (or at least, most people) would still like your scripts to run in this case.
- jbrnh 7y ago
  But if I write the script for a bunch of RHEL servers then OS X and brew are irrelevant, and the full path is better (IMHO). It's the 'always use env..' I object to.
  - moviuro 7y ago
    It's RHEL... today. `/usr/bin/env` is a POSIX standard. Maybe one day, RHEL will put bash in /usr/local/bin. Or maybe you'll switch to FreeBSD one day, and suddenly everything goes boom.
    - jbrnh 7y ago
      env and sh are both POSIX but AFAIK the path is not specified for either of them. If POSIX has an opinion on how you should start a script I would be happy for a link? Bash in RHEL is in /usr/bin and /bin as /bin in symlinked to /usr/bin. I think it is equally unlikely that RHEL (Debian, SLES..) will will move either /bin/bash or /usr/bin/env as it would break a million scripts out there. If we should migrate to FreeBSD while, for some reason, reusing linux oriented bash scripts, changing the path to /usr/local/bin/ would be the least of my headaches. I agree that 'env' can make good sense if you don't know who/where/when your script is used. For internal projects, I don't really see the advantage.
dredmorbius 7y ago
$ uname -a Linux localhost 3.10.49-5975984 #1 SMP PREEMPT Thu Oct 8 17:25:20 KST 2015 armv7l Android $ which env /data/data/com.termux/files/usr/bin/env https://xkcd.com/927/ https://xkcd.com/927/

by jbrnh 7y ago

YawningAngel 7y ago

'System bash' isn't a universal or clear concept. For example, if you're using Modern OS X, you likely have bash via brew or some other userspace package manager but no system bash. Presumably you (or at least, most people) would still like your scripts to run in this case.

jbrnh 7y ago
But if I write the script for a bunch of RHEL servers then OS X and brew are irrelevant, and the full path is better (IMHO). It's the 'always use env..' I object to.
- moviuro 7y ago
  It's RHEL... today. `/usr/bin/env` is a POSIX standard. Maybe one day, RHEL will put bash in /usr/local/bin. Or maybe you'll switch to FreeBSD one day, and suddenly everything goes boom.
  - jbrnh 7y ago
    env and sh are both POSIX but AFAIK the path is not specified for either of them. If POSIX has an opinion on how you should start a script I would be happy for a link? Bash in RHEL is in /usr/bin and /bin as /bin in symlinked to /usr/bin. I think it is equally unlikely that RHEL (Debian, SLES..) will will move either /bin/bash or /usr/bin/env as it would break a million scripts out there. If we should migrate to FreeBSD while, for some reason, reusing linux oriented bash scripts, changing the path to /usr/local/bin/ would be the least of my headaches. I agree that 'env' can make good sense if you don't know who/where/when your script is used. For internal projects, I don't really see the advantage.

dredmorbius 7y ago

$ uname -a Linux localhost 3.10.49-5975984 #1 SMP PREEMPT Thu Oct 8 17:25:20 KST 2015 armv7l Android $ which env /data/data/com.termux/files/usr/bin/env https://xkcd.com/927/ https://xkcd.com/927/