should I avoid bash -c, sh -c, and other shells' equivalents in my shell scripts?

Question

Consider the following code:

#!/bin/bash -x
VAR=\'1 2 3\'
bash -c \"echo \"\\$$VAR\"\"
eval \"echo \"\\$$VAR\"\"
bash -c \"echo \\\"\\$$VAR\\\"\"
eval \"echo         


        

Answer 1

As far as I am aware, there is no reason to use bash -c from a bash shell. Using it will start a new process, which is expensive.

You can use eval, which doesn't start a new process. If you want a sub-shell (for example, to preserve the environment) you can use parentheses.

Normally, bash -c (or other shells with -c) is used to execute a command from another non-shell environment (or perhaps a DSL interpreted by a shell) where shell expansion of the arguments is required. In the old days, you might use it with execvp in a C program, for example. These days, there are usually ways of running a command using a shell in most environments.