On 07Oct2020 11:07, Patrick O'Callaghan <pocallaghan@xxxxxxxxx> wrote:
>On Tue, 2020-10-06 at 15:45 -0700, ToddAndMargo via users wrote:
>> I start all my Raku programs with
>> 1: #!/usr/bin/env raku
>
>Why? If you aren't adding options to 'env', surely this is the same as
>using '/usr/bin/bash'.
No, this is a standard shebang (#!) hack to accomodate differering
installation paths. The #! requires a fixed absolute path. So things
which are often installed in different places (such as raku above) like
/usr/local/bin or /opt/something and accessed via the user's $PATH
setting, putting in this line makes the script more portable.
It does rely on "env" itself being in /usr/bin, but that is very
common. (Not universal, the a plenty of systems where I make a symlink
from /bin/env to /usr/bin/env to enable _exactly_ ToddAndMargo's
approach.)
Anyway, since env uses $PATH to locate the following executable, this
lets you write scripts for a typically-third-party interpreter portably.
My own common use case is:
#!/usr/bin/env python3
which runs my preferred python3 (usually the one in my personal
~/var/venv/3).
Cheers,
Cameron Simpson <cs@xxxxxxxxxx>
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