I typically use this with ./monitor.sh lsusb to tell when an nvidia jetson is in flashing mode.

Useful any time you find yourself typing the same command over and over again to check the status of something. Use it with nslookup to see when your DNS changes have propagated. Etc.

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#!/usr/bin/env bash

if [ "$#" -eq 0 ]; then
        echo "Usage: $0 <command_to_monitor> [arg1] [arg2] [...]"
        exit 1
fi

command_to_monitor=("$@")

while true; do
        result=$("${command_to_monitor[@]}")
        timestamp=$(date +"%Y-%m-%d %H:%M:%S")

        if [ "$result" != "$prev_result" ]; then
                printf "\e[1;34m%s\e[0m ------------ \n%s\n" "$timestamp" "$result"
                prev_result="$result"
        fi

        sleep 1
done