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spiffytech 01-01-2006 07:39 AM
How can I make my script check to see if a file is empty?
 
I need to make my script check to see if a text file is empty so I can fork the process depending on whether or not it is. How do I do that?

homey 01-01-2006 08:20 AM
Something like this...
Code:
#!/bin/bash
# Example: ./test file.txt

fsize=$(stat -c %s $1)

if [ $fsize -lt 1 ] ; then
  echo $1 is empty
  else
  echo $1 is not empty
fi

LiNuXkOlOnIe 01-01-2006 08:31 AM
Quote:
Originally Posted by homey
Something like this...
Code:
#!/bin/bash
# Example: ./test file.txt

fsize=`stat -c %s $1`

if [ $fsize -lt 1 ] ; then
  echo $1 is empty
  else
  echo $1 is not empty
fi
The new way of command-substitution and recommended is:
fsize = $(stat -c %s $1)

The result of both is the same. Not an advise only how i make it cos the backtick could be overseen in an hot programming session.

Happy new year.

homey 01-01-2006 08:38 AM
Thanks for the tip LiNuXkOlOnIe ! :)

jcliburn 01-01-2006 09:08 AM
Bash has a built-in test for this and many other file attributes (see the bash manpage). The "-s" option tests for a file with non-zero size.

Code:
#!/bin/bash

if [ -s $1 ]; then
        echo "File size is non-zero";
else
        echo "File size is zero";
fi

LiNuXkOlOnIe 01-01-2006 09:12 AM
Jaaauu. And the oscar goes tooo ...
jcliburn.

thank you.

Don't worry only spamming. :-)))

jcliburn 01-01-2006 09:35 AM
One caveat with the -s method... It returns false under TWO conditions: the file size is zero, OR if the file doesn't exist. So if you feed my sample script a nonexistent file name, it'll say "File size is zero".


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