Sleeping within nested for loops in bash -

i have pair of nested for loops in bash shell script.

i want pause script every 60 seconds when counter hits multiple of 50 "ticks" or iterations, put in modulo test:

counter=1 ((i=0; i<${#libraries[@]}; i++));     ((j=(i+1); j<${#libraries[@]}; j++));         # stuff...         if [ $counter%50 == 0 ];             sleep 60s         fi         counter=$[$counter+1]     done done 

this loop behaves erratically — specifically, script not pause every 50 iterations, staggers , skips or otherwise not appear triggering expected sleep call correctly.

whatever put # stuff... script not pause expected, behaves in same erratic way. can comment out — same behavior.

the ${#libraries[@]} stuff array of file paths.

does sleep not work inside loops, or not using correctly? there alternative way pause script without breaking out nested loops separate wrapper scripts?

i think test wrong. try instead :

if (( counter % 50 == 0 )) 

the $counter%50 part never expand 0, test fail, , sleep never executed. % modulo operator requires arithmetic context, standard test command not provide, double parentheses will.