How to split Bash array into arguments

Question

I wrote a bash script for listing python processes, ram usage and PID and status in human readable form with colored lines. But I have some trouble with working time of the script. Because of the repeatedly written ps commands working time is taking too much time.

SCRPITS=`ps x | grep python | grep -v ".pyc" | grep -v grep | awk  '{print $NF}'`

prepare_text () {
    if [[ ${2%.*} -gt ${RAMLIMIT} ]]; then
        # RED
        TEXT=`printf "\033[31m%-62s %'10d %2s %5s %6s\n\033[0m" "${1}" "${2}" "KB" "${3}" "${4}"`
    elif [[ ${2%.*} -gt ${RAMLIMIT}/2 ]]; then
        # YELLOW
        TEXT=`printf "\033[33m%-62s %'10d %2s %5s %6s\n\033[0m" "${1}" "${2}" "KB" "${3}" "${4}"`
    else
        # GREEN
        TEXT=`printf "\033[32m%-62s %'10d %2s %5s %6s\n\033[0m" "${1}" "${2}" "KB" "${3}" "${4}"`
    fi
    TEXTBODY+=${TEXT}
}

display () {
    printf "$SUBJECT\n"
    printf "%-62s %13s %5s %8s\n" "PROCESS" "RAM USAGE" "PID" "STATUS"
    printf "===========================================================================================\n"
    printf "${TEXTBODY}\n"
}


for SCRIPT in ${SCRPITS}
do
    USAGE=`ps aux | grep ${SCRIPT} | grep -v "grep" | awk '{print $6}'`
    PID=`ps aux | grep ${SCRIPT} | grep -v "grep" | awk '{print $2}'`
    STATUS=`ps aux | grep ${SCRIPT} | grep -v "grep" | awk '{print $8}'`
    prepare_text ${SCRIPT} ${USAGE} ${PID} ${STATUS}
done
display
exit $?

I decided to change that approach and I rearrange all script for shortening work time as below:

OIFS=$IFS #save original
IFS='\n'
SCRIPTS=`ps aux | grep python | grep -v ".pyc" | grep -v grep | awk '{print $NF,",",$5,",",$2,",",$8}'`
IFS=${OIFS}
prepare_text () {
    if [[ $((${2%.*})) -gt ${RAMLIMIT} ]]; then
        # RED
        TEXT=`printf "\033[31m%-62s %'10d %2s %5s %6s\n\033[0m" "${1}" "${2}" "KB" "${3}" "${4}"`
    elif [[ $((${2%.*})) -gt ${RAMLIMIT}/2 ]]; then
        # YELLOW
        TEXT=`printf "\033[33m%-62s %'10d %2s %5s %6s\n\033[0m" "${1}" "${2}" "KB" "${3}" "${4}"`
    else
        # GREEN
        TEXT=`printf "\033[32m%-62s %'10d %2s %5s %6s\n\033[0m" "${1}" "${2}" "KB" "${3}" "${4}"`
    fi
    TEXTBODY+=${TEXT}
}

display () {
    printf "$SUBJECT\n"
    printf "%-62s %13s %5s %8s\n" "PROCESS" "RAM USAGE" "PID" "STATUS"
    printf "===========================================================================================\n"
    OIFS=$IFS
    IFS=","
    set ${SCRIPTS}
    for SCRIPT in ${SCRIPTS}
    do
    prepare_text $1 $2 $3 $4
    done
    printf "\n\n"
    IFS=${OIFS}
    printf "${TEXTBODY}\n"
}


display
exit $?

Now I can get what information I want from ps at once but I have some problem with formatting and displaying that information.

I can't figure out how can I get each argument from ${SCRIPTS}, split them and pass to prepare_text function.

I guess I misunderstand something.

Answer 1

I suggest you extract the info that you need from ps, nothing else, and let awk (not bash) do the rest: grepping, comparisons, formatting. Example:

ps -ax --no-headers -o pid,vsz,stat,command |
awk -v lim=23000 '
# let awk do the grepping
/bash/ && !/awk/ {
  # save first 3 fields
  pid=$1
  vsz=$2
  stat=$3
  # rest is command line, possibly spanning multiple fields
  for (i=4;i<=NF;++i) $(i-3)=$i
  NF-=3
  # decide on color
  if (vsz>lim) col="\033[31m"
  else if (vsz>lim/2) col="\033[33m"
  else col="\033[32m"
  # printout
  printf("%s%-62s %10d KB %5s %6s%s\n",
    col, $0, vsz, pid, stat, "\033[0m")
}'

Tweak values, and add in headers as needed.