Use "/usr/bin/env" in shebangs #685
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Instead of directly executing stuff from /bin or /usr/bin, do it via /usr/bin/env to allow overriding the binaries via PATH. For example, if the user has some local installation of Bash or Python which is set as a priority in PATH, it will be used instead of the one from hardcoded /usr/bin location.
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Oh great, apparently, Linux has decided that there can be at most one argument on the shebang line, and this is common knowledge on the interwebs. Writing #!/usr/bin/env bash -eis not portable. |
Apparently, Linux kernel accepts at most one argument to the binary
on the shebang line. Everything after the space is treated as a single
argument. Obviously, the user is unlikely to have an executable called
"bash -e" in their PATH, so replace all
#!/bin/bash -e
with
#!/usr/bin/env bash
set -eu
instead of
#!/usr/bin/env bash -e
which fails on Linux.
(Yeah, enable not only "-e" but "-u" as well as it's a common mistake to
use unset variables due to typos or other errors.)
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I got a bit pissed off a bit by this behavior, thought that I might 'fix' it in the kernel. Oh boy, of course it has been discussed multiple times over the years with the general sentiment that it's a backwards incompatible change and hysterical raisins should have their way. A part of me understands the reasoning very well—too well—but another part is saddened by it. |
shadinua
approved these changes
Jul 28, 2020
The "-u" option makes it an error to use unset variables. Most of the
time it is an error to do so. Where it is not an error, the ${var:-?}
syntax should be used to provide explicit default value.
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@shadinua, I've added missing |
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Instead of directly executing stuff from
/binor/usr/bin, do it via/usr/bin/envto allow overriding the binaries via PATH. For example, if the user has some local installation of Bash or Python which is set as a priority in PATH, it will be used instead of the one from hardcoded/usr/binlocation.@shadinua has pointed out this observation in #681. This PR applies the same change throughout the entire code base for consistency. Now if someone uses existing scripts as examples, they should notice the
/usr/bin/envusage and do the same.Checklist