pgrep, pkill

gistfile1.sh

#!/bin/sh

# NAME
#       pgrep, pkill - find or signal processes by name and other attributes
#
# SYNOPSIS
#       pgrep [-glpfao] pattern
#       pkill [-glpfao] [-s SIG] pattern
#
# DESCRIPTION
#       pgrep looks through the currently running processes and lists the
#       process IDs which match the selection criteria to stdout.
#
#       pkill does the same, and sends them signals.
#
# OPTIONS:
#       -g      [glob] use pattern as a glob
#       -l      [literal] don't use pattern as a glob (default)
#       -p      [part] match pattern against part of the string
#       -f      [full] match pattern against the full string (default)
#       -a      [args] match against all the args
#       -o      [only] match only against argv[0] (default)
#
#       For pkill only:
#       -s SIG  a signal name or a number

pgrep () {
  read -r pspid
  while read -r pid name; do
    if ! [ "$pid" -eq "$$" ] && ! [ "$pid" -eq "$pspid" ]; then
      if "$glob" && "$full"; then
        case $name in $proc) echo "$pid"; ret=0;; esac
      elif "$glob" && ! "$full"; then
        case $name in *$proc*) echo "$pid"; ret=0;; esac
      elif ! "$glob" && "$full"; then
        case $name in "$proc") echo "$pid"; ret=0;; esac
      else
        case $name in *"$proc"*) echo "$pid"; ret=0;; esac
      fi
    fi
  done
  exit "$ret"
} << EOF
$output
EOF

pkill () {
  read -r pspid
  while read -r pid name; do
    if ! [ "$pid" -eq "$$" ] && ! [ "$pid" -eq "$pspid" ]; then
      if "$glob" && "$full"; then
        case $name in $proc) set -- "$@" "$pid"; ret=0;; esac
      elif "$glob" && ! "$full"; then
        case $name in *$proc*) set -- "$@" "$pid"; ret=0;; esac
      elif ! "$glob" && "$full"; then
        case $name in "$proc") set -- "$@" "$pid"; ret=0;; esac
      else
        case $name in *"$proc"*) set -- "$@" "$pid"; ret=0;; esac
      fi
    fi
  done
  if [ "$ret" -eq 0 ]; then
    kill "-$signal" "$@"  # kill may or may not print its own error message
  fi
  exit "$ret"
} << EOF
$output
EOF

basename=${0##*/} glob=false full=true args=comm signal=15 ret=1
while getopts :glpfaos: opt; do
  case $opt in
    g) glob=true;;
    l) glob=false;;
    p) full=false;;
    f) full=true;;
    a) args=args;;
    o) args=comm;;
    s) signal=$OPTARG
      if [ "$basename" = pgrep ]; then
        echo "Unknown option: -s" >&2; exit 1
      fi;;
    :) echo "Option -$OPTARG requires an argument" >&2; exit 1;;
    \?) echo "Unknown option: -$OPTARG" >&2; exit 1;;
  esac
done

shift $((OPTIND-1))
if [ "$#" -gt 1 ]; then
  echo "Only one pattern at a time" >&2
  exit 1
elif [ "$#" -lt 1 ]; then
  echo "Must provide a pattern to match" >&2
  exit 1
fi

output=$(sh -c "echo \$$; exec ps -A -o pid= -o $args=")
proc=$1 

if [ "$basename" = pgrep ]; then
  pgrep
elif [ "$basename" = pkill ]; then
  pkill
else
  echo "Error" >&2
  exit 1
fi