RhysU / zc

A variant on the idea behind https://github.com/rupa/z

zc

What is zc?

zc is a utility for tracking which directories you have recently visited. With a little shell integration effort, it permits "jumping around". The utility was written after some experimentation with rupa/z.

Relative to rupa/z's z.sh, zc has the following advantages:

1. zc isolates maintaining the recently-visited database from shell details.
2. zc uses flocks to avoid clobbering the database in, e.g., GNU Screen.
3. zc has the overhead like launching one single process.
4. zc has decent unit tests (try make check).
5. zc has some minimal performance testing (try make stress).

Relative to rupa/z, zc has the following disadvantages:

1. zc must be compiled and you have to read my lousy C.
2. The mechanism for cleaning up subsequently removed directories might be unfriendly to network filesystems.
3. Regex search is not implemented.
4. Bash integration (found below) requires bash-preexec.
5. Zero adoption by anyone but me.

How do I use it?

After creating some directories and visiting them once, attempting to jump to a directory containing 'q' is ambiguous. The ambiguity is broken by asking for the most recently visited match (-t):

$ mkdir -p foo/bar/baz/qux/quux
$ cd foo/bar/baz/qux/quux/
$ cd ..
$ cd ..
$ cd ..
$ cd ..
$ cd ..
$ z q
zc/foo/bar/baz/qux
zc/foo/bar/baz/qux/quux
$ z -t q
~/Build/zc/foo/bar/baz/qux ~/Build/zc

The above ambiguity could also be settled by providing, e.g., "quu". Instead of most recent time (-t), one could request highest rank (-r) according to number of visits or by "frecency" (-f). Multiple path elements could be used, e.g. ux ux, and all of them must match in order.

Notice z appeared above instead of zc. That's a consequence of the following installation.

How do I install it?

Installing zc involves something like the following in your .bashrc.

# Aliases ease using https://github.com/RhysU/zc against a particular database
if test -x "${HOME}/bin/zc"; then
    z_raw() { "$HOME/bin/zc" -d "$HOME/.zc"       "$@"; }
    z_add() { "$HOME/bin/zc" -d "$HOME/.zc" -a -- "$@"; }
else
    z_raw() { echo "RhysU/zc is not installed" 1>&2; false; }
    z_add() { :; }
fi

# Run http://github.com/RhysU/zc in some mode against fixed database.
# Whenever it succeeds and only one line is output, attempt to pushd there.
z() {
    local zout newline='
'
    if zout=$(z_raw "$@"); then
        case $zout in
          *"$newline"*) echo "$zout"          ;;  # 2+ matches => display
                    "") builtin pushd "$@"    ;;  # No match => use input
                     *) builtin pushd "$zout" ;;  # One match => use match
        esac
    fi
}
zf() { z -f -- "$@"; }  # Abbreviation
zr() { z -r -- "$@"; }  # Abbreviation
zt() { z -t -- "$@"; }  # Abbreviation

# Z becomes much more useful with tab completion hooks installed.
# Above z() must accommodate trailing slashes because of '-o filenames'.
_z_completion() {
    COMPREPLY=()
    while IFS=$'\n' read -r line; do
        COMPREPLY+=("$line")
    done < <(z_raw -k -- "${COMP_WORDS[@]:1}")
}
complete -o filenames -F _z_completion z

# On every command, record the working directory using z_add.
# Versus https://github.com/rupa/z, updating per-command nicer for GNU Screen.
# Also, the updates are lighter weight on account of backing zc implementation.
precmd_z() {
    # Only register non-HOME directories as HOME is just a 'cd' away.
    if [ "$PWD" != "$HOME" ]; then
        z_add "$PWD"
    fi
}

# Prompts use precmd/preexec hook per https://github.com/rcaloras/bash-preexec.
if [ -f "${HOME}/.preexec.bash" ]; then
    . "${HOME}/.preexec.bash"
    precmd_functions+=(precmd_z)
fi

Golfing is most welcome, especially golfing that addresses disadvantages. Not breaking Bash login on systems without either bash-preexec or zc available is desired.