UNIX下SH的实现源码

				#! /bin/bash				#				# center - center a group of lines				#				# tabs in the lines might cause this to look a little bit off				#				#								width=${COLUMNS:-80}								if [[ $# == 0 ]]				then					set -- /dev/stdin				fi								for file				do					while read -r					do						printf "%*s\n" $(( (width+${#REPLY})/2 )) "$REPLY"					done < $file				done								exit 0