Shell Programming and Scripting

#!/bin/bash
# sysrenan - www.sysrenan.com
# delete a percent of line within a file

if [ "$#" -eq 1 ]
then

    	SRC="$1"
        TOTAL=$(cat $SRC | wc -l)

        if [ "$?" -eq 0 ]
        then
            	echo "This log has $TOTAL lines";
                echo "Enter the % of lines you want to delete:";
                read linestodelete;

                DEL=$(($TOTAL * $linestodelete / 100));
                /bin/sed -i 1,$DEL\d $SRC;
        else
            	echo "Invalid file";
                exit 1;
        fi
else
    	echo "Incorrect number of arguments";
        echo "Usage: ./truncade <logfile>";
fi

sed --help

/bin/sed -i 1,$DEL\d $SRC;

/bin/sed 1,$DEL\d $SRC;

/bin/sed -e 1,$DEL\d $SRC;