watch equivalent in zsh

Question

In bash, watch (e.g. watch -n 5 ls -l) could be used to repeat the command at fixed intervals.

This command seem to be missing on zsh. Is there an equivalent?

Answer 1

watch is not an internal command:

$ type watch
/usr/bin/watch

so make sure it installed on the system where you are running zsh.

Answer 2

I just improvised watch with: clear; while ls -lah; do sleep 2; clear; done

Interesting idea. I could write a function around that... Right, put this in your .zshrc

watch () {
    IN=2
    case $1 in
        -n)
            IN=$2
            shift 2
            ;;
    esac
    printf '\033c' # clear
    CM="$*"
    LEFT="$(printf 'Every %.1f: %s' $IN $CM)"
    ((PAD = COLUMNS - ${#LEFT}))
    while :
    do
        DT=$(date)
        printf "$LEFT%${PAD}s\n" "$HOST $(date)"
        eval "$CM"
        sleep $IN
        printf '\033c'
    done
}