What does the -x and -c string comparison options do?

Question

I'm in the process of porting over another shell script when I came across the following:

if [[ ! -x $DVDREC ]]; then
  print "ERROR: $DVDREC not found. Exiting ..."
  exit 1
fi

if [[ ! -c ${DVDDEV} ]]; then
  print "ERROR: ${DVDDEV} not found. Exiting ..."
  exit 1
fi

I was wondering what the -c and -x options actually do with regards to the strings stored in DVDREC and DVDDEV?

score 3 · Answer 1 · answered Jul 03 '12 at 15:16

3

From "help test" in a bash shell:

  -c FILE        True if file is character special.
  -x FILE        True if the file is executable by you.

answered Jul 03 '12 at 15:16

jordanm

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score 3 · Answer 2 · answered Jul 03 '12 at 15:16

3

// man test

   -c FILE
          FILE exists and is character special

   -x FILE
          FILE exists and execute (or search) permission is granted

answered Jul 03 '12 at 15:16

rush

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score 3 · Answer 3 · answered Jul 03 '12 at 15:16

3

Citing man test:

   -c FILE
          FILE exists and is character special

   -x FILE
          FILE exists and execute (or search) permission is granted

answered Jul 03 '12 at 15:16

vitaut

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Thanks for your help. I'm fairly new to the Linux Operating System so I wasn't aware that there was a manpage for test. – Justin Jul 03 '12 at 15:19
1

@Justin: No problems. For people who are new to bash the relationship between `[` and `test` is not obvious. So it's a good question. – vitaut Jul 03 '12 at 15:26
1

@justin - the manpage isn't for the test command that you would be using. The `test` builtin or `[` would be used first. In your case, you are using a bash keyword `[[`, rather than a command. The flags are the same. – jordanm Jul 03 '12 at 15:27

What does the -x and -c string comparison options do?

3 Answers3