I have the script below to subtract the counts of files between two directories but the COUNT=
expression does not work. What is the correct syntax?
#!/usr/bin/env bash
FIRSTV=`ls -1 | wc -l`
cd ..
SECONDV=`ls -1 | wc -l`
COUNT=expr $FIRSTV-$SECONDV ## -> gives 'command not found' error
echo $COUNT
Try this Bash syntax instead of trying to use an external program expr
:
count=$((FIRSTV-SECONDV))
BTW, the correct syntax of using expr
is:
count=$(expr $FIRSTV - $SECONDV)
But keep in mind using expr
is going to be slower than the internal Bash syntax I provided above.