This is part of the Semicolon&Sons Code Diary - consisting of lessons learned on the job. You're in the bash category.
Last Updated: 2024-11-21
I encountered the following while working on a Dockerfile entrypoint
set -- php-fpm "$@"
What's going on?
The set command - when not used to set options, sets the positional parameters in bash.
# notice how `set` takes multiple arguments
$ set foo bar dog
$ echo $1
foo
$ echo $2
bar
$ echo $3
dog
$@ contains all the existing position parameters. Therefore set -- php-fpm
"$0" places php-fpm before $1, $2.
See for yourself:
$ set foo bar dog
$ set -- php-fpm "$@"
$ echo $1,$2,$3,$4
php-fpm,foo,bar,dog