bash : Multiple Unary operators in if statement

Question

hello, Is it possible to have multiple unary operators in if statements.. Here is the code snippet which is giving me error.

Please correct the code here.

if [ -f $input_file ] -a [ -f $output_file ] -a [ -f $log_file ] ]
then
### Some Code here
fi

Thanks Kiran

Answer 1

if [ -f "file1" -a -f "file2" -a "file3" ]; then
   #some code
fi

Answer 2

[ is a command, not part of the if statement. As such you should pass it each of the appropriate arguments instead of trying to incorrectly run it as you have.

if [ arg1 arg2 arg3 arg4 ... ]
then

Answer 3

You can see the [ ... ] operator only as a shortcut for test .... The options are used th same way.

So in your case you could either write the ghostdog74 way or :

if [ -f $input_file ] && [ -f $output_file ] && [ -f $log_file ]
then
### Some Code here
fi

Answer 4

If you use Bash's double-bracket, you can do this:

if [[ -f "$input_file" && -f "$output_file" && -f "$log_file" ]]

which I find cleaner to read than other options shown here (but that's subjective). However, it has other advantages.

And, as ghostdog74 shows, you should always quote variables containing filenames.