Well, some archived project is not so great either. The core functionality is not even a 20 line bash script since bash grew wait -n, though: #!/bin/bash

Well, some archived project is not so great either. The core functionality is not even a 20 line bash script since bash grew wait -n, though: #!/bin/bash if [ "${1-0}" -lt 1 ]; then # No arg / arg not a number >= 1 echo "Usage: $0 <N>"; echo "reads cmds from stdin, running up to N at once." exit 1 fi TMP=`mktemp -t stripen.XXXXXX` trap 'rm -f $TMP; exit 0' HUP INT TERM EXIT STRIPE_SEQ=1 while read cmd; do jobs > $TMP # jobs | wc -l does not work if [ $(wc -l < $TMP) -ge $1 ]; then wait -n # Wait for 1/more jobs to finish fi # Could accumulate total $? above, but would need to replace final wait. STRIPE_SEQ=$((STRIPE_SEQ + 1)) ( eval "$cmd" ) < /dev/null & # Run job in a subshell in bg done rm -f $TMP wait # Wait for all to finish and if bash ever grows some magic environment variable $NUM_BG_JOBS or you don't want auto-help or sequence numbers or etc. it can be even simpler.