Shell Programming and Scripting

#! /bin/bash

for i in `dirs` 
do
    echo ${i}
done
echo ++++++++++++++++++
for i in $( dirs -p )
do
    echo ${i}
done
echo ------------------
dirscontent=`dirs`
echo "dirs : $dirscontent"
echo ++++++++++++++++++

function dirslist () {
    declare -A arr
    for i in ~ /usr /usr/local /usr ~ /etc
#    for i in $( dirs -p )
    do
    echo checking ${i}
    if [ ${arr[$i]+7} ] ; then
        echo "         ${i} exists, should not try add it again"
    else
        echo "         adding $i to arr"
        arr[ $i ]=1
    fi
    done
    for key in "${!arr[@]}"; do
    echo "Key: $key"
    done
}

Key:  /home/myuser 
Key:  /etc 
Key:  /usr/local 
Key:  /usr

foreach directory in DIRSTACK
   if the directory has not been presented to the user
       present the directory to the user
       remember (i.e. store) the directory

function dirlist () {
    declare -A arr
    for i in /usr /usr/local /usr "/foldername with spaces"  "/foldername with spaces"
    do
    echo checking ${i}
    if [[ ${arr[$i]} != 17 ]] ; then
        echo "        handling $i and adding it to arr"
        arr[ $i ]=17
    fi
    done
}

checking /usr
        handling /usr and adding it to arr
checking /usr/local
        handling /usr/local and adding it to arr
checking /usr
        handling /usr and adding it to arr
checking /foldername with spaces
        handling /foldername with spaces and adding it to arr
checking /foldername with spaces
        handling /foldername with spaces and adding it to arr

checking /usr
        handling /usr and adding it to arr
checking /usr/local
        handling /usr/local and adding it to arr
checking /foldername with spaces
        handling /foldername with spaces and adding it to arr

unset -f cd
function cd () {
    local -i maxnrDirs=7
    local -i nrDirs=0     # index of dirs as shown to user 
    local visited=()
    local -i founddir=0
    
    # if argument is a valid directory , change directory
    if [ -d "$1" ]; then
	pushd "$1" > /dev/null;
    else
	for ((i=1; i < ${#DIRSTACK[@]}; i++)); do
	    # keep track of already listed directories,
	    # Note, should be done with associative array
	    # this was on my TODO list for 20 years
	    local -i found=0
	    for ((j=0; j < ${#visited[@]}; j++)); do
		if [[ ${visited[$j]} == ${DIRSTACK[${i}]} ]]
		then
		    found=17
		    break
		fi
	    done
	    # handle directory option if not found
	    if [ $found == 0 ] ; then
		((nrDirs+=1))
		# if there is no argument to cd, list previous dirs
		if [ -z "$1" ]; then
		    founddir=17
		    echo " $nrDirs ${DIRSTACK[$i]}"; 
		    # if there is a number argument, check against DIRSTACK 
		else
		    if [ "$1" == ${nrDirs} ]; then
			if [ "${DIRSTACK[${i}]}" ]; then
			    if [ -d "`dirs -l +${i}`" ]; then
				pushd "`dirs -l +${i}`" > /dev/null ;
				founddir=${i};
			    fi;
			fi;
		    fi;
		fi
		local dir=${DIRSTACK[$i]}  # for quoting directory with spaces
		visited+=("$dir")          # visited+=("${DIRSTACK[$i]}") does not work
		if [ $nrDirs == $maxnrDirs ]; then
		    break;
		fi
	    fi
        done;
	if [ ${founddir} == 0 ]; then
            # Handle special characters, invent new ones ....?
            if [ "$1" == - ]; then
		pushd "`dirs -l +1`" > /dev/null;
	    elif [ "$1" == "..." ]; then
		if [ -d "../../" ]; then
		    pushd "../../../" > /dev/null ;
		fi
	    elif [ "$1" == "...." ]; then
		if [ -d "../../../" ]; then
		    pushd "../../../" > /dev/null ;
		fi
            elif [ ! -z "$1" ]; then
		# error message, TODO check \ ??
		echo ${1} not a valid directory;
            fi;
	fi;
    fi
}

complete -A directory cd
complete -A directory pushd

/> export PS1='\w> '
/> cd /
/> dirs -c
/> cd /usr/
/usr> cd local/
/usr/local> cd /etc/
/etc> cd cron.d/
/etc/cron.d> cd
 1 /etc
 2 /usr/local
 3 /usr
 4 /
/etc/cron.d> cd 2
/usr/local> cd -
/etc/cron.d> cd
 1 /usr/local
 2 /etc/cron.d
 3 /etc
 4 /usr
 5 /
/etc/cron.d> dirs -p
/etc/cron.d
/usr/local
/etc/cron.d
/etc
/usr/local
/usr
/

echo ${DIRSTACK[@]}
/usr /etc/network /home/myuser /usr /mnt/9/plgr
declare -A TMP
for DN in ${DIRSTACK[@]}; do TMP[$DN]=1; done
select R in ${!TMP[@]}; do echo cd $R; break; done
1) /usr
2) /home/myuser
3) /etc/network
4) /mnt/9/plgr
#? 3
cd /etc/network