The fist "ls" is used to test if any files matching this criteria are found. The output of ls is "thrown away" (to /dev/null) - the point being to know if there are such files, not to list them. If files are found, the "if [ $? -eq 0 ]" will be true (the ls returned 0 meaning success - files were found). But ls will write to standard error if no files are found. You can get rid of the error by directing standard error to /dev/null too. The simplest way is to direct standard error to standard output (which you threw away to /dev/null), so...
Change:
Code:
ls -1rt abc[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9].txt > /dev/null
To:
Code:
ls -1rt abc[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9].txt > /dev/null 2>&1
I hope this was explanatory and not at all boring to read!
