Bash script that monitors a directory of source files for changes, then does something (like build) if changed.

monitor.sh

#!/bin/bash
# Bash script that monitors a directory of source files for changes, then does something (like build) if changed.
# It does this via creating a SHA of the ls tree of the folder in question, and if changed, triggers the action.
# The "action" is just the variable $command, normally make.
# Usage :
#   ./monitor.sh
#   Then save a file, and it gets built! Magic!

command="make"
params=""
if [ $1 ]; then
    echo "--> Monitor: Passing parameters :" $*
    params="$*"
fi

sha=0
previous_sha=0

update_sha()
{
    sha=`ls -lR . | egrep '\.cpp|\.h|\.spt' | sha1sum`
}

build () {
    ${command} ${params}
    echo
    echo "--> Monitor: Monitoring filesystem... (Press enter to force a build/update)"
}

changed () {
    echo "--> Monitor: Files changed, Building..."
    build
    previous_sha=$sha
}

compare () {
    update_sha
    if [[ $sha != $previous_sha ]] ; then changed; fi
}

run () {
    while true; do

        compare

        read -s -t 1 && (
            echo "--> Monitor: Forced Update..."
            build
        )

    done
}

echo "--> Monitor: Init..."
echo "--> Monitor: Monitoring filesystem... (Press enter to force a build/update)"
run

Bash script that monitors a directory of source files for changes, then does something (like build) if changed.
It does this via creating a SHA of the ls tree of the folder in question, and if changed, triggers the action.
The "action" is just the variable $command, normally make.
Usage :
./monitor.sh Then save a file, and it gets built! Magic!