A small group of utilities and aliases to effectively add backward and forward change directory functionality to bash, similar to how internet browser backward and forward navigation buttons work.

cdmod.md

cdmod

• cdmod_aliases.sh

  A group of bash aliases enhancing on the capability to change directory.

  More specifically, these aliases provide the abilities to change directory backward to previous directories (not to be mistaken with parent directories), to change directory forward to directories previously changed back from, and to view the directory history for the current terminal session including all backward directories, the current directory, and all forward directories. Just source this file from your ~/.bashrc or similar files and these aliases will all be applied at the beginning of each new terminal session.

cdmod_aliases.sh

# cd - Change Directory
# Overriden cd to add current working directory to the previous directory
# history and erase the forward directory history before changing directory.
# Unfortunately, due to the limitations of aliases, the forward directory
# history must be discarded regardless of whether or not a valid directory
# change is requested (ie. change to current directory or change to invalid
# directory, both resulting in not actually changing directory).
alias cd='
unset NEXT_DIRECTORIES
unset NEXT_DIRECTORIES_COUNT
if [ -z "$PREVIOUS_DIRECTORIES" ] || ([ -n "$PREVIOUS_DIRECTORIES" ] && [ "$PWD" != "${PREVIOUS_DIRECTORIES[$PREVIOUS_DIRECTORIES_COUNT-1]}" ]); then
    PREVIOUS_DIRECTORIES[((PREVIOUS_DIRECTORIES_COUNT++))]="$PWD"
fi
cd' # Do not put a newline between this cd and closing quotation, otherwise the alias will not work!

# b - Back
# Change directory back to the previous working directory.
alias b='
if [ -n "$PREVIOUS_DIRECTORIES" ]; then
    [ "${PREVIOUS_DIRECTORIES[$PREVIOUS_DIRECTORIES_COUNT-1]}" == "$PWD" ] && PREVIOUS_DIRECTORIES[((--PREVIOUS_DIRECTORIES_COUNT))]=
    PREVIOUS_DIRECTORY="${PREVIOUS_DIRECTORIES[$PREVIOUS_DIRECTORIES_COUNT-1]}"
    if [ -n "$PREVIOUS_DIRECTORY" ]; then
        PREVIOUS_DIRECTORIES[((--PREVIOUS_DIRECTORIES_COUNT))]=
        if [ -z "$NEXT_DIRECTORIES" ] || ([ -n "$NEXT_DIRECTORIES" ] && [ "$PWD" != "${NEXT_DIRECTORIES[$NEXT_DIRECTORIES_COUNT-1]}" ]); then
            NEXT_DIRECTORIES[((NEXT_DIRECTORIES_COUNT++))]="$PWD"
        fi
        \cd "$PREVIOUS_DIRECTORY"
    fi
fi
'

# f - Forward
# Change directory forward to the next working directory if a forward directory
# history has been made by changing directory backwards.
alias f='
if [ -n "$NEXT_DIRECTORIES" ]; then
    [ "${NEXT_DIRECTORIES[$NEXT_DIRECTORIES_COUNT-1]}" == "$PWD" ] && NEXT_DIRECTORIES[((--NEXT_DIRECTORIES_COUNT))]=
    NEXT_DIRECTORY="${NEXT_DIRECTORIES[$NEXT_DIRECTORIES_COUNT-1]}"
    if [ -n "$NEXT_DIRECTORY" ]; then
        NEXT_DIRECTORIES[((--NEXT_DIRECTORIES_COUNT))]=
        if [ -z "$PREVIOUS_DIRECTORIES" ] || ([ -n "$PREVIOUS_DIRECTORIES" ] && [ "$PWD" != "${PREVIOUS_DIRECTORIES[$PREVIOUS_DIRECTORIES_COUNT-1]}" ]); then
            PREVIOUS_DIRECTORIES[((PREVIOUS_DIRECTORIES_COUNT++))]="$PWD"
        fi
        \cd "$NEXT_DIRECTORY"
    fi
fi
'

# h - History
# Show the entire directory history including all previous directories, all
# forward directories, and the current directory.
alias h='
echo "Change Directory History:"
if [ -n "$PREVIOUS_DIRECTORIES_COUNT" ] && [ $PREVIOUS_DIRECTORIES_COUNT -gt 0 ]; then
    PREV_DIR_COUNT=$PREVIOUS_DIRECTORIES_COUNT
    [ "${PREVIOUS_DIRECTORIES[$PREVIOUS_DIRECTORIES_COUNT-1]}" == "$PWD" ] && ((PREV_DIR_COUNT--))
    for ((i=0; i<PREV_DIR_COUNT; i++)); do
        echo -e "\t${PREVIOUS_DIRECTORIES[$i]}"
    done
fi
echo -e "->\t$PWD"
if [ -n "$NEXT_DIRECTORIES_COUNT" ] && [ $NEXT_DIRECTORIES_COUNT -gt 0 ]; then
    NEXT_DIR_COUNT=$NEXT_DIRECTORIES_COUNT
    [ "${NEXT_DIRECTORIES[$NEXT_DIRECTORIES_COUNT-1]}" == "$PWD" ] && ((NEXT_DIR_COUNT--))
    for ((i=NEXT_DIR_COUNT-1; i>=0; i--)); do
        echo -e "\t${NEXT_DIRECTORIES[$i]}"
    done
fi
'

LICENSE

MIT License

Copyright (c) 2017 Nicholas Omer Chiasson

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
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