bcsh.sh

linux下bash的源码

				i="`expr \"$i\" : '.*\(!!.*\)'`"
				;;
			*!!*)
				front="`expr \"$i\" : '\(.*\)!!.*'`"
				i="`expr \"$i\" : '.*\(!!.*\)'`"
				;;
			!*)
				front=
				i="`expr \"$i\" : '.*!\(.*\)'`"
				;;
			*)
				tmp="$tmp$i "
				continue
				;;
			esac
			case "$i" in
			!!*)
				# want last command

				rest="`expr \"$i\" : '!!\(.*\)'`"
				i=$lastcmd
				;;
			-*)
				# we want to search back through the history list

				case "$i" in
				-)
					rest="`expr \"$i\" : '-\(.*\)'`"
					i=$lastcmd
					;;
				-[0-9]*)
					wanted="`expr \"$i\" : '-\([0-9][0-9]*\).*'`"
					rest="`expr \"$i\" : '-[0-9][0-9]*\(.*\)'`"
					i="`tail -$wanted $histfile | sed -e "1q"`"
					;;
				esac
				;;
			[0-9]*)
				# find which number command is wanted

				wanted="`expr \"$i\" : '\([0-9][0-9]*\).*'`"
				rest="`expr \"$i\" : '[0-9][0-9]*\(.*\)'`"
				i="`grep -n . $histfile | grep \"^$wanted\"`"
				i="`expr \"$i\" : \"${wanted}.\(.*\)\"`"
				;;
			\?*)

				# find which 'command-contains' match is wanted

				case "$i" in
				\?{*}*)
					wanted="`expr \"$i\" : '?{\(.*\)}.*'`"
					rest="`expr \"$i\" : '?.*}\(.*\)'`"
					;;
				\?*:*)
					wanted="`expr \"$i\" : '?\(.*\):.*'`"
					rest="`expr \"$i\" : '?.*\(:.*\)'`"
					;;
				\?*)
					wanted="`expr \"$i\" : '?\(.*\)'`"
					rest=
					;;
				esac
				i="`grep \"$wanted\" $histfile | tail -1`"
				;;
			*)
				# find which 'start-of-command' match is wanted

				case "$i" in
				{*}*)
					wanted="`expr \"$i\" : '{\(.*\)}.*'`"
					rest="`expr \"$i\" : '.*}\(.*\)'`"
					;;
				*:*)
					wanted="`expr \"$i\" : '\(.*\):.*'`"
					rest="`expr \"$i\" : '.*\(:.*\)'`"
					;;
				*)
					wanted="$i"
					rest=
					;;
				esac
				i="`grep \"^$wanted\" $histfile | tail -1`"
				;;
			esac

			# see if we actually found anything to substitute

			case "$i" in
			"")
				badsub="Event not found"
				break
				;;
			*)
				badsub=no
				;;
			esac

			case "$rest" in
			"")
				tmp="$front$tmp$i "
				continue
				;;
			:[0-9]*)
				# find which element of $i is wanted

				number="`expr \"$rest\" : ':\([0-9][0-9]*\).*'`"
				rest="`expr \"$rest\" : ':[0-9][0-9]*\(.*\)'`"

				# count through $i till we get to the
				# right element

				counter=0
				for element in $i
				do
					case "$counter" in
					$number)
						break
						;;
					*)
						counter="`expr \"$counter\" + 1`"
						# counter=$[ $counter + 1 ]
						;;
					esac
				done
				case "$counter" in
				$number)
					badsub=no
					;;
				*)
					badsub="Bad command element"
					break
					;;
				esac
				tmp="$tmp$front$element$rest "
				continue
				;;
			:\$*)
				# spin through $i till we hit the last element

				rest="`expr \"$rest\" : ':\$\(.*\)'`"
				for element in $i
				do
					:
				done
				tmp="$tmp$front$element$rest "
				continue
				;;
			:\**)
				# we want all elements except the command itself

				rest="`expr \"$rest\" : ':\*\(.*\)'`"
				save=$i
				set - $i
				shift
				case "$*" in
				"")
					badsub="No arguments to command '$save'"
					break
					;;
				*)
					badsub=no
					;;
				esac
				tmp="$tmp$front$*$rest "
				continue
				;;
			:s*|:gs*)
				# we are doing a substitution
				# put / on end if needed

				case "$rest" in
				:s/*/*/*|:gs/*/*/*)
					;;
				:s/*/*|:gs/*/*)
					rest="${rest}/"
					;;
				esac

				# find what substitution is wanted

				first="`expr \"$rest\" : ':*s\/\(.*\)\/.*\/.*'`"
				second="`expr \"$i\" : ':*s/.*/\(.*\)/.*'`"

				# see if it is a global substitution

				case "$rest" in
				:gs*)
					global=g
					;;
				:s*)
					global=
					;;
				esac
				rest="`expr \"$rest\" : '.*/.*/.*/\(.*\)'`"
				i="`echo \"$i\" | sed -e \"s@$first@$second@$global\"`"

				# see if subsitution worked

				case "$i" in
				"")
					badsub="Substiution failed"
					break
					;;
				*)
					badsub=no
					;;
				esac
				tmp="$tmp$front$i$rest "
				continue
				;;
			*)
				tmp="$tmp$front$i$rest "
				;;
			esac
		done
		case "$badsub" in
		no)
			;;
		*)
			echo "$badsub"
			badsub=no
			continue
			;;
		esac
		cmd="$tmp"
		echoit=yes
		getcmd=no
		continue
		;;
	*)
		run=yes
		;;
	esac

	case "$cmd" in
	*\^*\^*\^*)
		# see if the substitution is global
		case "$cmd" in
		g*)
			global=g
			;;
		*)
			global=
			;;
		esac

		# put a '^' on the end if necessary
		case "$cmd" in
		*\^)
			;;
		*)
			cmd="${cmd}^"
			;;
		esac

		# find what substitution is wanted

		first="`expr \"$cmd\" : '*\^\(.*\)\^.*\^.*'`"
		second="`expr \"$cmd\" : '*\^.*\^\(.*\)\^.*'`"
		rest="`expr \"$cmd\" : '*\^.*\^.*\^\(.*\)'`"
		cmd="`echo \"$lastcmd\" | sed -e \"s@$first@$second@$global\"`$rest"

		# see if the substitution worked

		case "$cmd" in
		"")
			echo "Substitution failed"
			continue
			;;
		esac
		echoit=yes
		getcmd=no
		continue
		;;
	*~e)
		echo "$cmd" | sed -e "s@~e@@" > /tmp/bcsh$$
		$EDITOR /tmp/bcsh$$
		cmd="`cat /tmp/bcsh$$`"
		getcmd=no
		continue
		;;
	*~v)
		echo "$cmd" | sed -e "s@~v@@" > /tmp/bcsh$$
		echo "$lastcmd" > /tmp/bcsh$$
		$VISUAL /tmp/bcsh$$
		cmd="`cat /tmp/bcsh$$`"
		getcmd=no
		continue
		;;
	exec[\ \	]*)
		tail -$savehist $histfile>/tmp/hist$$
		uniq /tmp/hist$$ > $histfile
		rm -f /tmp/*$$
		echo $cmd > /tmp/cmd$$
		. /tmp/cmd$$
		;;
	login[\ \	]*|newgrp[\ \	]*)
		tail -$savehist $histfile>/tmp/hist$$
		uniq /tmp/hist$$ > $histfile
		rm -f /tmp/*$$
		echo $cmd > /tmp/cmd$$
		. /tmp/cmd$$
		;;
	logout|exit|bye)
		if test -s "$logoutfile"
			then
			# sh $logoutfile
			$SHELL $logoutfile
		fi
		tail -$savehist $histfile > /tmp/hist$$
		uniq /tmp/hist$$ > $histfile
		rm -f /tmp/*$$
		exit 0
		;;
	h|history)
		grep -n . $histfile | tail -$history | sed -e 's@:@	@' | $PAGER
		continue
		;;
	h[\ \	]\|*|h[\ \	]\>*|h\|*|h\>*)
		cmd="`echo \"$cmd\" | sed -e \"s@h@grep -n . $histfile | tail -$history | sed -e 's@:@	@'@\"`"
		getcmd=no
		continue
		;;
	history[\ \	]*\|*|history[\ \	]*\>*)
		cmd="`echo \"$cmd\" | sed -e \"s@history@grep -n . $histfile | tail -$history | sed -e 's@:@ @'@\"`"
		getcmd=no
		continue
		;;
	source[\ \	]*)
		set - $cmd
		shift
		echo . $*  > /tmp/cmd$$
		. /tmp/cmd$$
		run=no
		;;
	wait)
		wait
		run=no
		;;
	.[\ \	]*)
		echo $cmd > /tmp/cmd$$
		. /tmp/cmd$$
		run=no
		;;
	cd|cd[\ \	]*)
		# check if it will work first, or else this shell will terminate
		# if the cd dies.  If you have a built-in test, you might want
		# to replace the try-it-and-see below with a couple of tests,
		# but it is probably just as fast like this.

		echo $cmd > /tmp/cmd$$
		if ($SHELL /tmp/cmd$$) ; then
			. /tmp/cmd$$
		fi
		run=no
		;;
	awk[\ \	]*|dd[\ \	]*|cc[\ \	]*|make[\ \	]*)
		# these are the only commands I can think of whose syntax
		# includes an equals sign.  Add others as you find them.

		echo "$cmd" > /tmp/bcsh$$
		;;
	setenv*|*=*)
		# handle setting shell variables, turning cshell syntax to Bourne
		# syntax -- note all variables must be exported or they will not
		# be usable in other commands

		echo "$cmd" > /tmp/cmd$$
		ed - /tmp/cmd$$ << ++++
		g/^setenv[ 	]/s/[ 	]/@/
		g/^setenv@/s/[ 	]/=/
		g/^setenv@/s///
		g/^set/s///
		.t.
		\$s/=.*//
		s/^/export /
		w
++++
		. /tmp/cmd$$
		rm -f /tmp/cmd$$
		run=no
		;;
	unset[\ \	]*|umask[\ \	]*|export[\ \	]*|set[\ \	]*)
		# handle commands which twiddle current environment

		$cmd
		run=no
		;;
	alias|alias[\ \	])
		if [ -f $aliasfile ]; then
			$PAGER $aliasfile
		fi
		lastcmd=$cmd
		run=no
		continue
		;;
	alias[\ \	]*)
		case "$cmd" in
		alias[\ \	]\|*|alias[\ \	]\>*)
			cmd="`echo \"$cmd\" | sed -e \"s@alias@cat $aliasfile@\"`"
			getcmd=no
			continue
			;;
		alias[\ \	]*[\ \	]*)
			;;
		*)
			echo "Syntax: alias name command"
			cmd=
			continue
			;;
		esac
		set - $cmd
		shift
		cmd="$*"

		# make sure there is always 1 blank line in file so
		# unaliasing will always work -- ed normally refuses
		# to write an empty file
		echo "" >> $aliasfile
		cat << ++++ >> $aliasfile
$cmd
++++

#		ed - $aliasfile << '++++'
#		g/alias[ 	]/s///
#		g/^['"]\(.*\)['"]$/s//\1/
#		g/^/s//alias	/
#		w
#++++

		sort -u -o $aliasfile $aliasfile
		doalias=yes
		cmd="alias $cmd"
		run=no
		;;
	unalias[\ \	]*)
		set - $cmd
		case "$#" in
		2)
			cmd=$2
			;;
		*)
			echo "Syntax: unalias alias_name"
			continue
			;;
		esac
		ed - $aliasfile << ++++
		/^$cmd[ 	]/d
		w
++++
		case "`set - \`wc -l $aliasfile\`;echo $1`" in
		1)
			# just removed last alias
			doalias=no
			;;
		esac
		run=no
		;;
	*)
		case "$doalias" in
		yes)
			set - $cmd
			tmp="`grep \"^$1 \" $aliasfile`"
			case "$tmp" in
			$1[\ \	]*)
				shift
				cmd=$*
				set - $tmp
				shift
				tmp=$*
				case "$tmp" in
				*\$*)
					# uses positional variables

					cmd="set - $cmd ; $tmp"
					getcmd=no
					continue
					;;
				*)
					cmd="$tmp $cmd"
					getcmd=no
					continue
					;;
				esac
				;;
			*)
				echo "$cmd" > /tmp/bcsh$$
				;;
			esac
			;;
		no)
			echo "$cmd" > /tmp/bcsh$$
			;;
		esac
		;;
	esac

	case "$cmd" in
	*+~+p)
		cmd="`expr \"$cmd\" : '\(.*\)+~+p'`"
		echoit=yes
		run=no
		;;
	esac

	case "$cmd" in
	"")
		continue
		;;
	*)
		case "$exclaim" in
		yes)
			cmd="`echo \"$cmd\" | sed -e 's@REALEXCLAMATIONMARK@!@g'`"
			echo "$cmd" > /tmp/bcsh$$
			;;
		esac
		case "$echoit" in
		yes)
			echo $cmd
			;;
		esac
		case "$run" in
		yes)
			case "${noclobber+yes}" in
			yes)
				case "$cmd" in
				*\>![\ \	]*)
					ed - /tmp/bcsh$$ << ++++
					g/>!/s//>/
					w
++++
					;;
				*\>\>*)
					;;
				*\>*)
					outfile="`expr \"$cmd\" : '.*>\(.*\)'`"
					case "$outfile" in
					\&*)
						;;
					*)
						set - $outfile
						outfile="$1"
						if test -s "$outfile"
						then
							case "${iclobber+yes}" in
							yes)
								echo $n "Overwrite ${outfile}? $c"
								read answer
								case "$answer" in
								y*)
									;;
								*)
									echo ':' > /tmp/bcsh$$
									;;
								esac
								;;
							*)
								echo "${outfile}: file exists"
								echo ':' > /tmp/bcsh$$
								;;
							esac
						fi
						;;
					esac
					;;
				esac
				;;
			*)
				case "$cmd" in
				*\>![\ \	]*)
					ed - /tmp/bcsh$$ << ++++
					g/>!/s//>/g
					w
++++
					;;
				esac
				;;
			esac
			(trap 'exit 1' 2 3; $BASH /tmp/bcsh$$)
			;;
		esac
		case "$cmd" in
		$lastcmd)
			;;
		*)
			case "$exclaim" in
			yes)
				cmd="`echo \"$cmd\" | sed -e 's@!@\\\\!@g'`"
				;;
			esac

			cat << ++++ >> $histfile
$cmd
++++
			lastcmd=$cmd

			case "$inc_cmdno" in
			yes)
				cmdno="`expr \"$cmdno\" + 1`"
				# cmdno=$[$cmdno + 1]
				;;
			esac
			;;
		esac
		;;
	esac

	# The next commented-out line sets the prompt to include the command
	# number -- you should only un-comment this if it is the ONLY thing
	# you ever want as your prompt, because it will override attempts
	# to set PS1 from the command level.  If you want the command number
	# in your prompt without sacrificing the ability to change the prompt
	# later, replace the default setting for PS1 before the beginning of
	# the main loop with the following:  PS1='echo -n "${cmdno}% "'
	# Doing it this way is, however, slower than the simple version below.
	 
	PS1="${cmdno}% "

	getcmd=yes
	echoit=no
	exclaim=no
done
exit 0

# Christine Robertson  {linus, ihnp4, decvax}!utzoo!globetek!chris