How to use aliases in a bash shell script
Aliases can be useful, on the Bash command line, but they are not enabled by default in non-interactice scripts.
Aliases can be used to avoid long command lines particularly if you pass the same set of arguments repeatedly, for example:
alias mycmd='podman run --env MYVARS_* --rm -it -v $PWD/.config:/myapp/.config myimage'
and then to use the alias on the CLI in a terminal window:
$ mycmd arg1 arg2 etc
I've been using aliases for many years, but it wasn't until today that I discovered that they didn't work in a non-interactive script.
#!/usr/bin/env bash
alias mycmd='podman run --env MYVARS_* --rm -it -v $PWD/.config:/myapp/.config myimage'
mycmd hello
and then running with:
chmod +x ./test_alias.sh
$ ./test_alias.sh
./test_alias.sh: line 4: mycmd: command not found
From the Bash Reference Manual alias expansion is disabled, by default,
for non-interactive shells. It can be enabled by using the shopt builtin command:
#!/usr/bin/env bash
alias mycmd='podman run --env MYVARS_* --rm -it -v $PWD/.config:/myapp/.config myimage'
shopt -s expand_aliases # (1)
mycmd hello
Of course, the Bash Reference Manual also says that functions are preferred over aliases for almost every purpose, which I probably would have been using if I had started writing the script