Shell Programming and Scripting

ERROR1="error: can only use 0 or 1 arguments.\nusage: maxlines.sh [directory]"
ERROR2="error: argument must be a directory.\nusage: maxlines.sh [directory]\n"
# Verify that more than one command line argument doesn't exist.
if [[ $# -gt 1 ]]
        then
                printf "$ERROR1"
                exit 1
fi
# Set the DIR variable to default to the current directory.
DIR="."
# Case #2 and 3.
# The number of arguments on the command line equals one.
if [[ $# -eq 1 ]]
        then
                # Is the directory entry a directory?
                if [[ -d $1 ]]
                        then
                        # Assign the command line argument to the variable, DIR.
                                DIR="$1"
                else
                        printf "$ERROR2"
                        exit 1
                fi
fi
# All case are processed with the following code.
# Change directory to the indicated variable content.
cd $1
# Assign file name with highest number of new lines to the variable FILE.
FILE=$(wc -l `ls` 2>/dev/null| sort -u | tail -5 | head -5)
# Print statement for all cases.
printf "File `echo $FILE | awk '{print $1}'` has the maximum lines with `echo $wc -l| awk '{print $1}'` lines.\n"
exit 0

x=$(wc -l $(ls) |sort|grep -v total|tail -1)
echo "${x##* } is the largest file having  ${x%%* } lines"