BASH parallell jobs

BASH parallel jobs

#!/bin/bash
PID_LIST=""
for i in `seq 1 9`; do
	sleep 3s && echo $? > /tmp/PID_${!} &
	PID_LIST="${PID_LIST} $!"
	echo "Started process with pid $!"
done
wait
for pid in ${PID_LIST}; do
	echo "PID: ${pid} EXIT: $(</tmp/PID_${pid})"
	rm /tmp/PID_${pid}
done

# # You can get notification when a child exits:
# set -o monitor        # enable script job control
# trap 'echo "child died"' CHLD
#!/bin/bash

FILE_COUNT=`ls *.mp3 2> /dev/null |wc -l`
if [ ${FILE_COUNT} -gt 0 ]; then
	FILES=`ls *.mp3`
	PID_LIST=""
	PID_DIR=`/usr/bin/mktemp --tmpdir=/tmp --directory nikon-get.XXXXXX`
	MAX_PROCS=4
	CUR_PROCS=0
	for file in $FILES; do
		if [[ ${CUR_PROCS} -ge ${MAX_PROCS} ]] ; then
			wait;
			CUR_PROCS=0;
		fi

		############# DO SOME COMMAND HERE #############
		${HOME}/bin/mp3tag --artist="Dude" ${file} \
			&& echo $? > ${PID_DIR}/$! &   # This is to store PID in a file.
		#############     END COMMAND      #############

		CUR_PROCS=$((${CUR_PROCS}+1))
	done
	wait;
fi