BASH- string assignment with a string name containing a variable

Question

I have been going crazy trying to figure out this syntax...can anyone point me in the right direction?

#Counter to iterate through the ENTIRE affinity array
affArrayCtr=0

#Counter to go through 4 cores for EACH pid     
affCtr=0

#Counter to go through each PID to keep track of which PID we are on
pidCtr=0

#Affinity array size
affArraySz=${#affConfigArray[@]}

#Each core's new affinity, strings initialized to empty
pid0Aff=
pid1Aff=
pid2Aff=
pid3Aff=

while [ $affArrayCtr -lt $affArraySz ]; do

        while [ $affCtr -lt $NUMCORES ]; do

                if [[ ${affConfigArray[$affArrayCtr]} -eq 1 ]]; then
                        tempAff0="$(pid"${pidCtr}"Aff)"
                        tempAff1=$(($affArrayCtr % 4))
                        pid${pidCtr}Aff="$tempAff0 $tempAff1"

                        affCtr=$(($affCtr + 1))
                        affArrayCtr=$(($affArrayCtr + 1))
                fi

                affArrayCtr=$(($affArrayCtr + 1))
                affCtr=$(($affCtr + 1))
        done

        affCtr=0
        pidCtr=$(($pidCtr + $NUMCORES))


done

echo "Final affinity strings before adding the commas"
echo $pid0Aff

The problem is where I try to assign tempAff0="$(pid"${pidCtr}"Aff)" and when I try to do a final concatenation pid${pidCtr}Aff="$tempAff0 $tempAff1".

I attempted to make the change where I use arrays instead of strings, however, I am still having an issue with the fact that my array name contains a variable:

#Each core's new affinity, arrays initialized to empty
declare -a pid0Aff
declare -a pid1Aff
declare -a pid2Aff
declare -a pid3Aff

while [ $affArrayCtr -lt $affArraySz ]; do

        affCtr=0

        while [ $affCtr -lt $NUMCORES ]; do

                if [[ ${affConfigArray[$affArrayCtr]} -eq 1 ]]; then

                        tempAff=$(($affArrayCtr % 4))
                        pid${pidCtr}Aff[${#pid${pidCtr}Aff[*]}]="$tempAff"

                        affCtr=$(($affCtr + 1))
                        affArrayCtr=$(($affArrayCtr + 1))
                fi

The culprit is here where I want to append to the array:

pid${pidCtr}Aff[${#pid${pidCtr}Aff[*]}]="$tempAff"

CPerkins · Accepted Answer · 2013-10-22 13:07:47Z

1

Alternate solution: instead of trying to dynamically create a variable name, replace your individual varialbes pid0Aff, pid1Aff, etc with an array(e.g., pidAff), and use pidCtr to index it.

This should put you on the right track:

#! /bin/bash
pidAff[0]='zero'
pidAff[1]='one'
pidAff[2]='two'
pidAff[3]='three'

pidAffArrayCtr=0
pidAffArraySz=4

while [ $pidAffArrayCtr -lt $pidAffArraySz ]; do
    echo "pidAff of $pidAffArrayCtr is ${pidAff[$pidAffArrayCtr]}"
    pidAffArrayCtr=$(($pidAffArrayCtr + 1))
done

edited Oct 22, 2013 at 13:07

answered Oct 21, 2013 at 19:02

CPerkins

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1 Comment

c alvarado Over a year ago

So I attempted this solution, and am still having an issue with having a variable in my array name. I declare an array and have an issue here:

anubhava · Accepted Answer · 2013-10-21 19:02:11Z

0

Use BASH indirection as:

echo "${!tempAff0} ${!tempAff1}"

answered Oct 21, 2013 at 19:02

anubhava

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