A bash script to continuously curl a host, checking for a pattern/set of patterns in the result using grep. It prints random length noise at the end of the output to make it easier to see the text moving out of the corner of your eye--great for multiple (4) screens.

continuous_curl.sh

#!/bin/bash


function arg_or_default()
{
    if [ -n "$1" ]; then
        echo "$1"
    else
        echo "$2"          
    fi                     
}                          
                           
                           
function main()            
{                          
    while :                
    do                     
        suffix=""          
        random_length=$(($RANDOM % $max_noise_length))
                           
        for (( noise_counter=0; noise_counter<$random_length; noise_counter++ ))
        do                 
            suffix="$suffix$noise_character"
        done               
                           
        curl_result="$(tput setaf 1)FAILURE$(tput sgr0)"
        if [ -n "$(curl --silent --max-time $(($max_curl_time + 0)) $host_address | grep -E ""${grep_pattern}"" )" ]; then
            curl_result="$(tput setaf 2)SUCCESS$(tput sgr0)"
        fi                 
                           
        echo " - $curl_result $(date) $suffix"
                           
        sleep $sleep_time_between_calls
    done                   
}                          
                           
                           
# Set the defaults for these or pass the variables via command line
host_address=$(arg_or_default "$1" "10.98.76.11")
max_noise_length=$(arg_or_default "$2" 9)
noise_character=$(arg_or_default "$3" "*")
grep_pattern=$(arg_or_default "$4" "<html.*35")
max_curl_time=$(arg_or_default "$5" 1)
sleep_time_between_calls=$(arg_or_default "$6" 2)

# Call the main function which curls/sleeps/rinse/repeats
main