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I'm stuck with the following problem.

I've defined an alias in .bashrc (and .bash_profile):

alias echo2="echo"

This works well:

$ echo2 "test"

However, if I try to use it after a redirect, it doesn't work:

ls | awk '{print "echo2 "$1}' | bash
bash: line 1: echo2: command not found
bash: line 2: echo2: command not found

Does someone know why? How I could make it work?

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up vote 5 down vote accepted

You're piping it into a new bash process as input. That process doesn't load your initialization scripts though, so there's no alias defined.

Check the section INVOCATION in man bash: Depending on the file in which you defined the alias, you need to make the bash process either a login shell (-l) or interactive (-i) to load that file.

There's an additional restriction: Aliases are ignored when the shell isn't interactive. There's a workaround though:

   Aliases  are not expanded when the shell is not interactive, unless the
   expand_aliases shell option is set using shopt (see the description  of
   shopt under SHELL BUILTIN COMMANDS below).

Alternatively, you could look into using shell functions instead of aliases.

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