"args" could be replaced by "comm" to not filter grep. grep could be replaced by awk: ps -A -opid,comm | awk '($2 == "haproxy") {printf "%d ",$1}' However

"args" could be replaced by "comm" to not filter grep. grep could be replaced by awk: ps -A -opid,comm | awk '($2 == "haproxy") {printf "%d ",$1}' However, "pidof haproxy" would work too.