Greetings, I need to extract a file based on a control file that I am reading and create an output file. My control file has 3 char and rows may look like : ABC DEF GHI The file I am extracting that is my source file has those lebels as follows: #ABC# line1 line2 #DEF# line3 ----- Based on what I have on my control file, I will need to either extract only my needed lines for the assinged control or just comment out all other lines except that has a label on the control. What is the easiest way to do this? Many thanks

So, each line in your control file specifies a block of lines to extract from your data file? cat infile #ABC# line 1 line 2 line 3 #DEF# line 4 line 5 line 6 line 7 #GHI# line 8 #JKL# line 9 line 10 #ZZZ# cat ctlfile GHI ABC JKL DEF For each line in the control file, the following script will extract the referenced block of lines into a separate file.  Each output file will be named out.??? while read ctlword do sed -n "/#$ctlword#/,/#...#/p" infile > "out.$ctlword" done < ctlfile I will use the head command to display the out files ... head out* ==> out.ABC <== #ABC# line 1 line 2 line 3 #DEF# ==> out.DEF <== #DEF# line 4 line 5 line 6 line 7 #GHI# ==> out.GHI <== #GHI# line 8 #JKL# ==> out.JKL <== #JKL# line 9 line 10 #ZZZ# A problem with extracting from/to ranges is that the triggering from and to lines are included.  The following script has additional sed commands to weed out the triggering lines: while read ctlword do sed -ne "/#$ctlword#/,/#...#/ba" -e b -e :a -e /#...#/!p infile > "out.$ctlword" done < ctlfile head out* ==> out.ABC <== line 1 line 2 line 3 ==> out.DEF <== line 4 line 5 line 6 line 7 ==> out.GHI <== line 8 ==> out.JKL <== line 9 line 10 But you probably want all of the extracted lines in a single file, so the following version stacks all output into one file. rm outfile 2> /dev/null while read ctlword do sed -ne "/#$ctlword#/,/#...#/ba" -e b -e :a -e /#...#/!p infile >> outfile done < ctlfile cat outfile line 8 line 1 line 2 line 3 line 9 line 10 line 4 line 5 line 6 line 7