I cannot seem to run this properly... It stucks and does not display an output - performance

Question

Here's my script:
while [[ $startTime -le $endTime ]]
do
thisfile=$(find * -type f | xargs grep -l $startDate | xargs grep -l $startTime)
fordestination=`cut -d$ -f2 $thisfile | xargs cut -d ~ -f4`
echo $fordestination
startTime=$(( $startTime + 1 ))
done

Answer 1

I think your cut and grep commands could get stuck. You probably should make sure that their parameters aren't empty, by using the [ -n "$string" ] command to see if $string isn't empty. In your case, if it were empty, it wouldn't add any files to the command that would use it afterwards, meaning that the command would probably wait for input from the command line (ex: if $string is empty and you do grep regex $string, grep wouldn't receive input files from $string and would instead wait for input from the command line). Here's a "complex" version that tries to show where things could go wrong:
while [[ $startTime -le $endTime ]]
do
thisfile=$(find * -type f)
if [ -n "$thisfile" ]; then
thisfile=$(grep -l $startDate $thisfile)
if [ -n "$thisfile" ]; then
thisfile=$(grep -l $startTime $thisfile)
if [ -n "$thisfile" ]; then
thisfile=`cut -d$ -f2 $thisfile`
if [ -n "$thisfile" ]; then
forDestination=`cut -d ~ -f4 $thisfile`
echo $fordestination
fi
fi
fi
fi
startTime=$(( $startTime + 1 ))
done
And here's a simpler version:
while [[ $startTime -le $endTime ]]
do
thisfile=$(grep -Rl $startDate *)
[ -n "$thisfile" ] && thisfile=$(grep -l $startTime $thisfile)
[ -n "$thisfile" ] && thisfile=`cut -d$ -f2 $thisfile`
[ -n "$thisfile" ] && cut -d ~ -f4 $thisfile
startTime=$(( $startTime + 1 ))
done
The "-R" tells grep to search files recursively, and the && tells bash to only execute the command that follows it if the command before it succeeded, and the command before the && is the test command (used in ifs).
Hope this helps =)