Log all output

log-all-output.sh

#! /bin/sh

LOG_FILE="/tmp/script-output.log"

function watchTail() {
  local cur_pid=$$
  local tail_args=`echo "tail -f $LOG_FILE" | cut -c1-79`
  local pid=`ps -e -o pid,ppid,args | grep ${cur_pid} | grep "${tail_args}"| grep -v grep | nawk '{print $1}'`

  if [ "$pid" = "" ]
  then
    if [ -z "$PS1" ]; then exit 0; else return 0; fi
  fi

  local ppid=2
  while [ "$ppid" != "1" ]
  do
    local pids=`ps -e -o pid,ppid,args | grep "${tail_args}"| grep ${pid} | grep -v grep | nawk '{print $1"-"$2}'`
    if [ "$pids" == "" ]; then break; fi
    local ppid=`echo ${pids} | nawk -F- '{print $2}'`
    if ((ppid==1))
    then
      sleep 3
      kill -9 $pid
    fi
  done
}

# Output to log file
exec 1>"$LOG_FILE" 2>&1

# Starting to print log file on screen
term=`tty`
if [ -z "`echo $term | grep "/dev/"`" ]
then
term=""
  tail -f "$LOG_FILE"
else
  tail -f "$LOG_FILE">$term &
fi

# Starting watch in background and process
watchTail &

# Begin script
echo "Hello world!"