Run dmenu with history of launched programs

dmenu-history.sh

#!/bin/sh
# default history path = ~/.cache/
cachedir=${XDG_CACHE_HOME:-"$HOME/.cache"}
histsize=50     # size of the history file
cache=$cachedir/dmenu
hist=$cachedir/dmenu_history
# if there isn't a history file - create it
if [ ! -e "$hist" ]; then
    touch "$hist"
    echo foo
fi

# this basically gets a history file and goes through it line-by-line and deleting duplicates (because piping history file and list of all executables creates duplicates)
cmd=$(
    awk -v histfile=$hist '
    BEGIN {
        while( (getline < histfile) > 0 ) {
            sub("^[0-9]+\t","")
            print
            x[$0]=1
        }
    } !x[$0]++ ' "$cache" \
    | dmenu "$@")

case $cmd in 
    * )   ${cmd};
          # add cmd to history (in the first line)
          sed -i -e "/^${cmd}$/d;${histsize}q" "$hist";
          sed -i "1s/^/${cmd}\n/" "$hist" ;;
esac

# delete empty lines if user aborts choosing
sed -i '/^\s*$/d' "$hist"