In the following script when I get SIZE1 and SIZE2, they are of type string. I can not do any mathematical operations(especially comparing which file has more byte size) on them. I wanted to find out if I can convert string in to Number. Thanks in Advance. FILE1='/export/registry/incoming/reg.dmp' FILE2='/export/registry/reg.dmp' SIZE1=`ls -l $FILE1 | awk '{print $5}'` SIZE2=`ls -l $FILE2 | awk '{print $5}'` if [ $SIZE1 > $SIZE2 ] then echo $SIZE1 - $SIZE2 else echo "The 1st file is smaller." fi

Use the operators -ge, -lt, -eq, -ne for integer comparisons.

Just to be perfectly clear in case there is a little confusion: -qe is 'greater than or equal to', -lt 'less than', -eq 'equal to', -ne 'not equal'.

Sorry, that first one should be -ge, not -qe

In ksh, zsh and bash you can use arithmetic expressions, e.g: if (( SIZE1 > SIZE2 )) then print "$SIZE1 is larger than $SIZE2" else print "The 1st file is smaller." fi This also gives you a standard set of operators, >=, +=, ++, -- etc.