path: root/sh/profile.d/options.sh

# Cache the options available to certain programs.  Run all this in a subshell
# (none of its state needs to endure in the session)
(
options() {

    # Check or create the directory to cache the options
    # Shift the program name off; remaining arguments are the options to check
    dir=$HOME/.cache/sh/opt/$1
    prog=$1
    shift

    # Directory already exists; bail out
    [ -d "$dir" ] && return

    # Create the directory and step into it
    mkdir -p -- "$dir" || return
    cd -- "$dir" || return

    # Write the program's --help output to a file, even if it's empty
    # This probably only works with GNU tools in general
    "$prog" --help </dev/null >help 2>/dev/null || return

    # Iterate through remaining arguments (desired options), creating files to
    # show they're available if found in the help output
    for opt do
        command grep -q -- \
            '[^[:alnum:]]--'"$opt"'[^[:alnum:]]' help || continue
        touch -- "$opt"
    done
}

# Cache options for bc(1)
options bc \
    quiet

# Cache options for ed(1)
options ed \
    verbose

# Cache options for grep(1)
options grep \
    binary-files \
    color \
    devices \
    directories \
    exclude \
    exclude-dir

# Cache options for ls(1)
options ls \
    almost-all \
    block-size \
    color \
    human-readable \
    quoting-style \
    time-style
)