Scrolling through a file at a readable speed

Sometimes you want to tail or read a file at a speed that you can distinguish content, or at which your brain can at least spot anomalies. This script can help you with that.

user@host:~$ cat bin/slow-scroll 
#!/bin/bash
[ "${1}" == "-r" ] && {
    MAX=${2:-0.1}
    while read LINE ; do
        echo ${LINE}
        sleep $(echo ${RANDOM} / 32767 \* ${MAX} | bc -ql)s
    done
} || {
    SLEEP_TIME=${1:-0.08}
    while read LINE ; do
        echo ${LINE}
        sleep ${SLEEP_TIME}s
    done
}

---

Usage: slow-scroll [ delay ] | -r [ max-delay ]

The script outputs a line of its input every <delay> seconds. <delay> defaults to 0.08 which I have found to work well for spotting oddities as a logfile passes by. Pause the output with Ctrl-Z and resume with fg.

If the '-r' flag is given, the delay is randomised between 0 and <max-delay> seconds, which defaults to 0.1. I will say nothing more about this functionality than point you towards this comic from http://jaymz.eu/.

The script is optimised for the common case (i.e. not using "-r") hence the seemingly inefficient code duplication. I don't want a sequence of subshells spawning if I'm using this on a server, which would be required if one were to roll the logic into one loop without some flag variables being set and tested each time through the loop. YMMV.