#!/bin/bashread var1 <data-fileecho "var1 = $var1"# var1 set to the entire first line of the input file "data-file"read var2 var3 <data-fileecho "var2 = $var2   var3 = $var3"# Note non-intuitive behavior of "read" here.# 1) Rewinds back to the beginning of input file.# 2) Each variable is now set to a corresponding string,#    separated by whitespace, rather than to an entire line of text.# 3) The final variable gets the remainder of the line.# 4) If there are more variables to be set than whitespace-terminated strings#    on the first line of the file, then the excess variables remain empty.echo "------------------------------------------------"# How to resolve the above problem with a loop:while read linedo  echo "$line"done <data-file# Thanks, Heiner Steven for pointing this out.echo "------------------------------------------------"# Use $IFS (Internal Field Separator variable) to split a line of input to# "read", if you do not want the default to be whitespace.echo "List of all users:"OIFS=$IFS; IFS=:       # /etc/passwd uses ":" for field separator.while read name passwd uid gid fullname ignoredo  echo "$name ($fullname)"done </etc/passwd   # I/O redirection.IFS=$OIFS              # Restore original $IFS.# This code snippet also by Heiner Steven.#  Setting the $IFS variable within the loop itself#+ eliminates the need for storing the original $IFS#+ in a temporary variable.#  Thanks, Dim Segebart, for pointing this out.echo "------------------------------------------------"echo "List of all users:"while IFS=: read name passwd uid gid fullname ignoredo  echo "$name ($fullname)"done </etc/passwd   # I/O redirection.echoecho "\$IFS still $IFS"exit 0