xyzzy - Great system admin command for Bash for switching between directories

xyzzy

#!/bin/bash

i="$1"
i=$((${i//[^0-9]/}))
i="$(($i-1+0))"

b="$2"
b=$((${b//[^0-9]/}))
b="$(($b-1+0))"

if [ -z "$XYZZY_INDEX" ]; then
	XYZZY_INDEX="$((-1))"
fi

if [ ! -f "/tmp/xyzzy.list" ]; then
	touch /tmp/xyzzy.list
	chmod a+rw /tmp/xyzzy.list
fi
readarray -t MYLIST < /tmp/xyzzy.list

showHelp(){
read -r -d '' MYHELP <<'EOB'
xyzzy 1.0

A command for manipulating escape routes from grues. Otherwise known as a useful system admin
tool for storing current directories and cycling through them rapidly. You'll wonder why this
wasn't created many moons ago.

Usage: xyzzy [options]

help/-h/--help		Show the help.

this/-t/--this		Store the current directory in /tmp/xyzzy.list

begone/-b/--begone	Clear the /tmp/xyzzy.list file. However, succeed with a number and
			it clears just that item from the stored list.

show/-s/--show		Show the list of stored directories from /tmp/xyzzy.list

. #			Use a number to 'cd' to that directory item in the stored list. This syntax is odd:

			. xyzzy 2

			...would change to the second directory in the list

. [no options]		Use the command alone and it cd cycles through the next item in the stored 
			list, repeating to the top when it gets to the bottom. The dot and space before xyzzy
			is required in order for the command to run in the current shell and not a subshell:

			. xyzzy

Note that you can avoid the odd dot syntax by adding this to your ~/.bashrc file:

  alias xyzzy=". xyzzy"

and then you can do "xyzzy" to cycle through directories, or "xyzzy {number}" to go to a
specific one.

May you never encounter another grue.

Copyright (c) 2016, Mike McKee <https://github.com/volomike>
EOB
	echo -e "$MYHELP\n"
}

storeThis(){
	echo -e "With a stroke of your wand, you magically created the new escape route: $PWD"
	echo "$PWD" >> /tmp/xyzzy.list
	chmod a+rw /tmp/xyzzy.list
}

begoneList(){
	if [[ "$b" == "-1" ]]; then
		echo "POOF! Your escape routes are gone. We bless your soul from the ever-present grues!"
		>/tmp/xyzzy.list
		chmod a+rw /tmp/xyzzy.list
	else
		echo -n "Waving your wand in the dark, you successfully manage to remove one of your escape routes: "
		echo "${MYLIST[${b}]}"
		>/tmp/xyzzy.list
		chmod a+rw /tmp/xyzzy.list
		for x in "${MYLIST[@]}"; do
			if [[ ! "$x" == "${MYLIST[${b}]}" ]]; then
				echo "$x" >> /tmp/xyzzy.list
			fi
		done
	fi
}

showList(){
	echo -e "These are your escape routes:\n"
	cat /tmp/xyzzy.list
}

cycleNext(){
	MAXLINES=${#MYLIST[@]}
	XYZZY_INDEX=$((XYZZY_INDEX+1))
	if [[ $XYZZY_INDEX > $(($MAXLINES - 1)) ]]; then
		XYZZY_INDEX=0
	fi
	MYLINE="${MYLIST[${XYZZY_INDEX}]}"
	cd "$MYLINE";
}

switchDir(){
	MYLINE="${MYLIST[${i}]}"
	cd "$MYLINE";
}

if [[ "$@" == "" ]];
then
	cycleNext
fi;

while [[ "$@" > 0 ]]; do case $1 in
	help) showHelp;;
	--help) showHelp;;
	-h) showHelp;;
	show) showList;;
	-s) showList;;
	--show) showList;;
	list) showList;;
	this) storeThis;;
	--this) storeThis;;
	-t) storeThis;;
	begone) begoneList;;
	--begone) begoneList;;
	*) switchDir;;
	esac; shift
done

export XYZZY_INDEX

The way I use this is to copy into /usr/bin folder and then chmod a+x on it. Then, I edit my root and user account ~/.bashrc file to include these lines at the bottom:

alias xyzzy='. xyzzy'
alias xy='. xyzzy'

The 'xy' is a shortened form of the command for faster typing.

Then, I can store the current directory in the list with...

xyzzy this

...and repeat as necessary.

Once I fill this list with the directories I need, they remain there until I reboot the computer because that's when /tmp is cleared out again. I can then type...

xyzzy show

...to list the currently saved directories. In order to switch to a directory, I have two choices. One option is to specify the path by index (and it's a 1-based index) like so:

xyzzy 2

...which would switch to the directory that's the second item in the list. Or, I could leave off the index number and just do:

xyzzy

...to have it loop through each directory as I need. For more commands you can do, type:

xyzzy help

Of course, work is more fun with the silly echo statements that I added in.

Note that xyzzy is a reference to the Collosal Cave text adventure, where typing xyzzy would let you switch between two rooms in the game in order to avoid grues.