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.