I like to rename a file based on the first line. Here is an example of what I need to do. File: 034568.dat has 2000 lines with first line as HIOSPAD23409JHK90000 I like to extract 3 characters from 5th column and rename the file to PAD_034568.dat. Really appreciate your help. Viv

When you're sure it works, change 'cp' to 'mv': #!/bin/ksh # no error checking myfile=034568.dat prevar=$(head -1 "$myfile"| cut -c5-7) cp "$myfile" "${prevar}_${myfile}"

Thanks for your response, being a UNIX novice I have another Q related to this... Now if I want to put this into a script to execute against unknown filename(s), how would I accomplish that?! Thanks

Consider this: #!/bin/ksh # UNTESTED cd /your/directory for myfile in $* do if [[ -f $myfile ]] then prevar=$(head -1 "$myfile"| cut -c5-7) cp "$myfile" "${prevar}_${myfile}" fi done The above script changes to a /your/directory. That's where your files are. If your script is called x.ss, execute it with your file names: x.ss 034568.dat file2.dat file3.dat if the file exists, it executes the commands.

awk 'FNR==1{ cmd = "mv "FILENAME" "substr($0,5,3)"_"FILENAME system(cmd) }' *.dat