Diff for "BashFAQ/011"

Anchor(faq11)

How can I print the n'th line of a file?

The dirty (but not quick) way would be:

    sed -n ${n}p "$file"

but this reads the whole input file, even if you only wanted the third line.

This one avoids that problem:

    sed -n "$n{p;q;}" "$file"

At line $n the command "p" is run, printing it, with a "q" afterwards: quit the program.

Another way, more obvious to some, is to grab the last line from a listing of the first n lines:

   head -n $n $file | tail -n 1 

Another approach, using ["AWK"]:

   awk "NR==$n{print;exit}" file

If you want more than one line, it's pretty easy to adapt any of the previous methods:

   sed -n "$x,${y}p;${y}q;" "$file"                # Print lines $x to $y; quit after $y.
   head -n $y "$file" | tail -n $(($y - $x + 1))   # Same
   awk 'NR>=$x{print} NR==$y{exit}' "$file"        # Same

Using cat(1) (and grep(1) (and cut(1))):

   cat -n file | grep '^  *<number of line>' | cut -f 2