Shell Programming and Scripting

Hi Don,

Sorry its AIX 6. I changed the pfile instead of filename but still result is same.

My question is we are giving cmp only one parameter but 2nd parameter we are not giving which should be recursive picking file name one by one from directory structure /u50/payments1. Sorry to disturb you again and again.

Thanks

No. The {} in:

Code:

-exec cmp -s "$Filename" {} \;

is replaced by the pathname of a file to be tested by find and it works perfectly when I try it on my MacBook Pro running OS X Yosemite. The only reason to get that diagnostic message from cmp is if the variable name used in the for loop does not match the variable name expanded in the find -exec primary or something else on that line does not match the text I suggested.

Please change the 1st line of your script to the following two lines:

Code:

#!/usr/bin/ksh
set -xv

rerun your script, and show us the exact output it produces (in CODE tags).

Thanks Don. I will run it tomorrow and let you know.

---------- Post updated 02-10-15 at 10:44 AM ---------- Previous update was 02-09-15 at 09:16 PM ----------

This is what I got

Getting list of parameters.
File Name is: /home/rkath/o34620760.out

Getting list of files to purge from /xxtd/u20/xx_payments:

Code:

for pfile in "$Filename"
do	ls -l "$pfile" | (
		read x x user group x
		find /xxtd/u20/xx_payments -user "$user" -group "$group" -type f \
			-exec cmp -s "$pfile" {} \; \
			-exec echo rm {} +
		echo rm "$pfile"
	)
done

Code:

+ ls -l /home/rkath/o34620760.out
+ read x x user group x
+ find /xxtd/u20/xx_payments -user rkath -group staff -type f -exec cmp -s /home/rkath/o34620760.out {} ; -exec echo rm {} +
Usage: cmp [-l | -s] File1 File2
+ echo rm /home/rkath/o34620760.out
rm /home/rkath/o34620760.out
return 0
+ return 0

There is a HUGE difference between the code you have here and what I suggested in post #10 in this thread:

Code:

for pfile in "$@"

Since Filename is an undefined variable in this script, $Filename expands to an empty string while "$@" expands to a list of your command-line arguments. Please try it the way I suggested in the first place.

Thanks a lot Don. Your script was not working in my environment but thanks a lot I learned a lot from you during this process. I finally wrote mine which is working fine now:

Code:

for f in $(find /home/u11/payments -type f)
do
echo comapring file now "$f" with $Filename
cmp -s $Filename $f > /dev/null
if [ $? -eq 1 ]; then
    echo is different    
else
    echo is not different
    echo Removing file now $f
    rm $f
fi
done

Moderator's Comments:

Please use CODE tags when displaying all sample input, output, and code segments.

This might work, but you're living dangerously...

The exit code from cmp is 0 if the files have the same contents, 1 if the contents are different, or some value greater than 1 if an error occurred. Your if condition is ignoring the error case and treating it as if the files compared equal when the comparison was not completed. (This might cause you to remove files that you couldn't compare.)

There is no need to redirect standard output from cmp -s since nothing is written to standard output when the -s option is present.

You might want to try this alternative (although I would still like to see a trace showing what failed in the script I suggested in post #10):

Code:

find /home/u11/payments -type f | while read -r f
do	printf 'Comparing file "%s" with "%s"...\n' "$f\" "$Filename"
	if cmp -s -- "$Filename" "$f"
	then	printf 'is not different\nRemoving "%s" now\n' "$f"
		rm -- "$f"
	else	echo 'is different or error encountered'
	fi
done

Using find ... | while read f allows the find command and the compare loop to run in parallel.

Using for f in $(find ...) requires the find command to complete before the compare loop starts.

Although your current filenames might not contain any spaces, tabs, or other characters special to the shell, quoting the expansions of $f and $Filename will keep your script running smoothly if conditions like that arise in the future. Similarly, preceding the file name operands to cmp and rm with -- protects against file names that might start with a minus sign (-) from being interpreted as options instead of as operands. And, the behavior of echo varies from system to system and shell to shell if the 1st operand given to echo starts with a minus sign or if any operand contains a backslash (\) character (both of which are possible from the expansions of $f and $Filename in your script). Using printf with a format string operand instead of echo avoids these possible problems.

Hope this helps...