How do I use Head and Tail to print specific lines of a file

head -n XX # <-- print first XX linestail -n YY # <-- print last YY lines

If you want lines from 20 to 30 that means you want 11 lines starting from 20 and finishing at 30:

head -n 30 file | tail -n 11# # first 30 lines#                 last 11 lines from those previous 30

That is, you firstly get first 30 lines and then you select the last 11 (that is, 30-20+1).

So in your code it would be:

head -n $3 $1 | tail -n $(( $3-$2 + 1 ))

Based on firstline = $2, lastline = $3, filename = $1

head -n $lastline $filename | tail -n $(( $lastline -$firstline + 1 ))

Aside from the answers given by fedorqui and Kent, you can also use a single sed command:

#!/bin/shfilename=$1firstline=$2lastline=$3# Basics of sed:#   1. sed commands have a matching part and a command part.#   2. The matching part matches lines, generally by number or regular expression.#   3. The command part executes a command on that line, possibly changing its text.## By default, sed will print everything in its buffer to standard output.  # The -n option turns this off, so it only prints what you tell it to.## The -e option gives sed a command or set of commands (separated by semicolons).# Below, we use two commands:## ${firstline},${lastline}p#   This matches lines firstline to lastline, inclusive#   The command 'p' tells sed to print the line to standard output## ${lastline}q#   This matches line ${lastline}.  It tells sed to quit.  This command #   is run after the print command, so sed quits after printing the last line.#   sed -ne "${firstline},${lastline}p;${lastline}q" < ${filename}

Or, to avoid any external utilites, if you're using a recent version of bash (or zsh):

#!/bin/shfilename=$1firstline=$2lastline=$3i=0exec <${filename}  # redirect file into our stdinwhile read ; do    # read each line into REPLY variable  i=$(( $i + 1 ))  # maintain line count  if [ "$i" -ge "${firstline}" ] ; then    if [ "$i" -gt "${lastline}" ] ; then      break    else      echo "${REPLY}"    fi  fidone

try this one-liner:

awk -vs="$begin" -ve="$end" 'NR>=s&&NR<=e' "$f"

in above line:

$begin is your $2$end is your $3$f is your $1