Sedding

First let’s generate some text to practice on

cat --help > randtxt

Compare the line numbers from the command nl with and without the option -nl

cat randtxt | nl
cat randtxt | nl -ba

The second is good for telling us actual line numbers in the file because it counts the blank lines..

Now we can do a replace command for the word FILE.

cat randtxt | sed 's/FILE/DAFTAR/g' # without g, only the first occurance in the line is replaced

What if we just want to replace the match on the 3rd line? or certain line ranges?

cat randtxt | sed '5 s/FILE/DAFTAR/g'

Extracting lines containing text matches. These commands are equivelant

cat randtxt | nl -ba | sed -ne '/FILE/p'
cat randtxt | nl -ba | grep 'FILE'

Specifying line ranges for printing (or deleting d, or replacing s):

cat randtxt |sed -ne '3p'       # printing specific line numbers
cat randtxt |sed -ne '3,7p'
cat randtxt |sed -ne '3,$p'     # to the end of the file
cat randtxt |sed -ne '3,+2 p'   # to 2 lines after the the 3rd line