Following ARG_MAX, maximum length of arguments for a new process it seems like ARG_MAX is wrongly (or at least ambiguously) defined on my Mac Mini 3,1 running Ubuntu 12.04:
$ getconf ARG_MAX # arguments 2097152 $ locate limits.h | xargs grep -ho 'ARG_MAX[ \t]\+[0-9]\+' | uniq | cut -d ' ' -f 8 131072 The actual limit seems to be somewhere between these:
$ cd "$(mktemp -d)" $ touch $(seq 1 131072) && find . -mindepth 1 -printf x | wc -c && rm * 131072 $ touch $(seq 1 131073) && find . -mindepth 1 -printf x | wc -c && rm * 131073 $ touch $(seq 1 $(getconf ARG_MAX)) && find . -mindepth 1 -printf x | wc -c && rm * bash: /usr/bin/touch: Argument list too long I did a small search:
cd "$(mktemp -d)" min=131072 max=2097152 while true do search=$((min + (max - min) / 2)) if touch $(seq 1 $search) 2>/dev/null then min=$search else max=$search fi [[ $((max - min)) -le 1 ]] && echo "ARG_MAX = $min" && break done Eventually this resulted in ARG_MAX = 314290, which doesn't seem to have any relation to either of the ARG_MAX values found before. Is this normal? Is there a simpler way to find the actual ARG_MAX?
Did I misunderstand the definition of ARG_MAX? It seems it's actually the byte (or possibly character) length of the arguments with or without (?) the separating spaces. If it's really the byte length, are there also other restrictions?
