Question

In a bash script, I have to check for the existence of several files.

I know an awkward way to do it, which is as follows, but that would mean that my main program has to be within that ugly nested structure:

if [ -f $FILE1 ] then if [ -f $FILE2 ] then   echo OK   # MAIN PROGRAM HERE fi fi 

The following version does not work:

([ -f $FILE1 ] && [ -f $FILE2 ]) ||  ( echo 'NOT FOUND'; exit 1 ) echo OK 

It prints

NOT FOUND OK 

Is there an elegant way to do this right?

UPDATE: See the accepted answer. In addition, in terms of elegance I like Jonathan Leffler’s answer:

arg0=$(basename $0 .sh) error() {     echo '$arg0: $@' 1>&2     exit 1 }  [ -f $FILE2 ] || error '$FILE2 not found' [ -f $FILE1 ] || error '$FILE1 not found' 

Answer 1

How about

if [[ ! ( -f $FILE1 && -f $FILE2 ) ]]; then     echo NOT FOUND     exit 1 fi  # do stuff echo OK 

See help [[ and help test for the options usable with the [[ style tests. Also read this faq entry.

Your version does not work because (...) spawns a new sub-shell, in which the exit is executed. It therefor only affects that subshell, but not the executing script.

The following works instead, executing the commands between {...} in the current shell.

I should also note that you have to quote both variables to ensure there is no unwanted expansion or word splitting made (they have to be passed as one argument to [).

[ -f '$FILE1' ] && [ -f '$FILE2' ] || { echo 'NOT FOUND'; exit 1; }