Useful menu and interactive snippets

#!/bin/bash

# useful snippets for menus and user-interactive scripts. For reference only
# All will loop until user chooses to quit (blank, menu choice, cancel)

# Read
while read -r -p "Tell me your city (ENTER to quit): " city && [[ $city ]]; do
    echo "You live in $city"
done

# One-liner (for pasting in #bash)
while read -r -p "Name (ENTER to quit): " name && [[ $name ]]; do { echo "Hello $name"; } done


# Array of options for select. Globs can be used for files
options=("AAA" "BBB" "CCC")


# Select Method 1 (fancier): add a last entry for Quit

# Only way to customoze select prompt is via PS3
PS3="Choose an option: "

# Select the with options, with an n+1 "Quit" entry added
echo "Select exemple 1:"
select entry in "${options[@]}" "Quit"; do

    # Test for last entry (size of options +1) and exit select (break)
    (( "$REPLY" != "${#options[@]}"+1 )) || { echo "Goodbye!" ; break; }

    # Test invalid options ($entry="") and try again (continue)
    [[ "$entry" ]] || { echo "Invalid option" ; continue; }

    #do stuff
    echo "You picked $entry which is option $REPLY"

done


# Method 2 (simpler): Non-existant entry 0 for quit
echo "Select exemple 2:"
PS3="Pick a choice (0 to quit): "
select entry in "${options[@]}"; do

    [[ ! "$REPLY" = "0" ]] || { echo "Goodbye!" ; break; }
    [[ "$entry" ]] || { echo "Invalid option" ; continue; }

    echo "You picked $entry which is option $REPLY"

done


# Method 1 with case

title="Select example"
prompt="Pick an option:"

echo "$title"
PS3="$prompt "
select opt in "${options[@]}" "Quit"; do

    case "$REPLY" in

    1 ) echo "You picked $opt which is option $REPLY";;
    2 ) echo "You picked $opt which is option $REPLY";;
    3 ) echo "You picked $opt which is option $REPLY";;

    $(( ${#options[@]}+1 )) ) echo "Goodbye!"; break;;
    *) echo "Invalid option. Try another one.";continue;;

    esac

done


# Loop with zenity (GUI)

while opt=$(zenity --title="$title" --text="$prompt" --list --column="Options" "${options[@]}"); do

    case "$opt" in
    "${options[0]}" ) zenity --info --text="You picked $opt which is option 1";;
    "${options[1]}" ) zenity --info --text="You picked $opt which is option 2";;
    "${options[2]}" ) zenity --info --text="You picked $opt which is option 3";;
    *) zenity --error --text="Invalid option. Try another one.";;
    esac

done


# Select with case (upon user request in #bash)

list=("Christmas" "Independence Day" "Thanksgiving" "Easter" "Memorial Day")
echo "Holliday selector"
PS3="Pick your favorite holliday (0 to quit): "
select entry in "${list[@]}"; do

    case "$REPLY" in
    0) echo "Bye sucker!"; break;;
    1) echo "$entry: Merry Chri'mah, bitch!";;
    2) echo "$entry: Party hard, nigga!";;
    3) echo "$entry: Happy Turkey Day! (now go get fat)";;
    4) echo "$entry: Jesus done come back to life, fools!!";;
    5) echo "$entry: Summer's here, you wankers!! School's OUT!";;
    *) echo "Sorry. The programmer was lazy and didn't list that many holidays. Try another one.";continue;;
    esac

done