Question

I currently use this function to wrap executing commands and logging their execution, and return code, and exiting in case of a non-zero return code.

However this is problematic as apparently, it does double interpolation, making commands with single or double quotes in them break the script.

Can you recommend a better way?

Here’s the function:

do_cmd() {     eval $*     if [[ $? -eq 0 ]]     then         echo 'Successfully ran [ $1 ]'     else         echo 'Error: Command [ $1 ] returned $?'         exit $?     fi } 

Answer 1

'$@' 

From http://www.gnu.org/software/bash/manual/bashref.html#Special-Parameters:

@

Expands to the positional parameters, starting from one. When the expansion occurs within double quotes, each parameter expands to a separate word. That is, ‘$@’ is equivalent to ‘$1’ ‘$2’ …. If the double-quoted expansion occurs within a word, the expansion of the first parameter is joined with the beginning part of the original word, and the expansion of the last parameter is joined with the last part of the original word. When there are no positional parameters, ‘$@’ and $@ expand to nothing (i.e., they are removed).

This means spaces in the arguments are re-quoted correctly.

do_cmd() {     '$@'     ret=$?     if [[ $ret -eq 0 ]]     then         echo 'Successfully ran [ $@ ]'     else         echo 'Error: Command [ $@ ] returned $ret'         exit $ret     fi }