3 ms·
> should have "set -eu" at its second line Do you have a strong reason to prefer "set" over shebang flags? I have a slight preference for shebang flags so I ca
by zwp 10y ago
> should have "set -eu" at its second line
Do you have a strong reason to prefer "set" over shebang flags? I have a slight preference for shebang flags so I can deliberately override them from the command line (but it's not a hill I'd die on):
$ cat foo
#!/bin/bash -eu
cd /nowhere
echo 'still here'
$ ./foo
./foo: line 2: cd: nowhere: No such file or directory
$ bash -c ./foo # thinking about system(3)
./foo: line 2: cd: nowhere: No such file or directory
$ bash +e ./foo # override
./foo: line 2: cd: nowhere: No such file or directory
still here
$
EDIT: Google's shell style guide has "Executables must start with #!/bin/bash and a minimum number of flags. Use set to set shell options so that calling your script as bash <script_name> does not break its functionality."
https://google.github.io/styleguide/shell.xml?showone=Which_Shell_to_Use#Which_Shell_to_Use https://google.github.io/styleguide/shell.xml?showone=Which_...
- vog 10y agoBash is not always /bin/bash. On some systems (BSDs) it is /usr/bin/bash. So the portable sh'bang line for bash is: #!/usr/bin/env bash And there you can't add "-eu" anymore, because only one argument is possible in sh'bang lines. (/usr/bin/env would try to find an executable named "bash -eu") So #!/usr/bin/env bash set -eu is the more portable approach. However, for "/bin/sh" this should work portably: #!/bin/sh -eu
- saghm 10y ago> Bash is not always /bin/bash. On some systems (BSDs) it is /usr/bin/bash. Nitpick: on every BSD system I've used, it's /usr/local/bin/bash. But I definitely agree that using /usr/bin/env bash is the preferred solution for when you want to use bash (although I don't think it's even installed by default on most BSD's); as an Arch user (where /usr/bin/python is symlinked to python3 rather than python2), I appreciate those who go out of their way to use proper, portable shebangs.