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Question

Why aliases in a non-interactive Bash shell do not work

Answer 1

+1 A:

You have to

shopt -s expand_aliases

in the file pointed to in your BASH_ENV

Vinko Vrsalovic 2009-10-23 21:12:14

Yeah that can be done, but it still does not work for me.

Nishith 2009-10-23 21:18:50

You need expand_aliases

Vinko Vrsalovic 2009-10-23 21:41:41

Thanks, it works now

Nishith 2009-10-23 21:50:00

Answer 2

+5 A:

.bashrc is only processed by interactive shells.

In addition, aliases are not expanded when the shell is not interactive, unless the expand_aliases shell option is set using shopt. Unless, of course, POSIX mode is invoked by calling the shell with the name sh instead of bash.

People who use aliases a lot often source their .bashrc at the end of their profile so that the aliases are there even for non-interactive shells. This might not be the best way, but it is pretty common.

It's things like this that lead me to believe that in the 21st century we should abandon shell scripts in favor of a full-blown language like Python. It's a lot more predictable.

Michael Dillon 2009-10-23 21:18:26

python makes for an abysmal interactive language. You can't cut/paste random bits of code unless the whitespace is exactly what you need.tclsh makes for a darn decent shell though -- it has built-in the ability to exec shell commands if the command you type isn't a known tcl command. Plus, it's very nature makes interactive use feasible.However, as much as a fan of Tcl that I am, I still prefer good ol' bash for interactive use. It's a pity tksh never quite reached escape velocity.

Bryan Oakley 2009-10-23 21:27:25

The /etc/profile trick will only work for non-interactive shells being supplied the --login option

Vinko Vrsalovic 2009-10-23 21:40:02

You are right, Python makes an abysmal interactive language. You should use bash. But if you have to write a script, do it in Python. Since it is an object-oriented language, you reuse bits of code by writing them as classes, methods and functions. Scripting is the same as programming so use a powerful programming language like Python. But for interaction, for two or three command pipelines, bash is fine.

Michael Dillon 2009-10-23 22:15:20

Opinion alert! Opinion alert! (Not that there is inherently anything wrong with Python -- save it being dynamically typed O.o -- but Ruby and Perl (and who knows what else) are also good contenders in that market)

pst 2009-10-23 22:26:32

Answer 3

+2 A:

The command shopt -s expand_aliases will allow alias expansion in non-interactive shells.

Jim Lewis 2009-10-23 21:24:21

Thanks Michael and Jim, it works now.

Nishith 2009-10-23 21:45:39

Answer 4

A:

This doesn't work.

asdf 2009-11-06 18:26:51

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Why aliases in a non-interactive Bash shell do not work

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