UNIX for Dummies Questions & Answers

Hi

I would like to rename Multiple files in a Unix Directory using Ksh Command.

Eg ATT8-2011-10-01 00:00:00-MSA-IMM-SINGLE_AND_FAMILY_COVERAGE-DED-$2000-X114817.PDF

needs to be renamed as

ATT8-2011-10-01-MSA-IMM-SINGLE_AND_FAMILY_COVERAGE-DED-$2000-X114817.PDF

Basically the time portion which is always 00:00:00 needs to be stripped off and the space between the date and the next hyphen symbol (-) needs to be compressed.

Any ideas as to how to this ? Assuming they are about 3000 files in the directory.

Code:

$ touch "ATT8-2011-10-01 00:00:00-MSA-IMM-SINGLE_AND_FAMILY_COVERAGE-DED-$2000-X114817.PDF"
$ ls *.PDF
ATT8-2011-10-01 00:00:00-MSA-IMM-SINGLE_AND_FAMILY_COVERAGE-DED-000-X114817.PDF
$ rename 's/\ 00:00:00//' *.PDF
$ ls *.PDF
ATT8-2011-10-01-MSA-IMM-SINGLE_AND_FAMILY_COVERAGE-DED-000-X114817.PDF
$

However, run the "no action" option first and double-check if it spits the right result.

Code:

       -n, --no-act
               No Action: show what files would have been renamed.

Nonetheless, a making a backup of directory containing the files prior to the actual renaming process is *highly* recommended. You never know...

@junior-helper: thread opener stated he uses Korn shell, so chances are this is not a Linux system at all. There is a good chance that the "rename"-command is not there.

Basically this is a simple job: create a loop in which you run a command mv "$oldname" "$newname" in which you rename one file after the other:

Code:

find /path/to/your/files -type <f -name optional-file-mask> |\
while read OLDNAME ; do
     mv "$OLDNAME" "$NEWNAME"
done

Which leaves the question where "$NEWNAME" comes from. You could use any text-modifying utility (sed, awk, ....) of which Unix is so rich of to construct the new name from the old. This utility would be called once for every single file and this would add a lot of overhead to your script, which should be avoided.

Fortunately the shell itself offers a great way to modify strings too, without having to resort to an external utility: the "parameter expansion" or "variable epansion". The syntax looks awkward at first, but its execution speed beats every external utility by some order of magnitude. Twenty lines of this is perhaps still way faster than a single awk- (sed-, ...) call.

I suggest having a look into the man page for details, here is the solution for your problem as you stated it: remove a middle " 00-00-00" from a string:

Code:

find /path/to/your/files -type <f -name optional-file-mask> |\
while read OLDNAME ; do
     chBegin="${OLDNAME%% 00:00:00*}"
     chEnd="${OLDNAME##* 00:00:00}"
     NEWNAME="${chBegin}${chEnd}"
     print - "OLDNAME: $OLDNAME"
     print - "chBegin: $chBegin    chEnd: $chEnd"
     print - "NEWNAME: $NEWNAME"

     print - mv "$OLDNAME" "$NEWNAME"
done

Run with the print-statements to see how it works, remove them once you feel comfortable with the output.

I hope this helps.

bakunin