Script to search a file:

#!/bin/sh -e

ls

printf "Enter the name of the file to search: "
read file_name

if [ -z "$filename" ]; then
    printf "File name cannot be empty.\n" >> /dev/stderr
    exit 65
fi

if [ ! -f $file_name ]; then
    printf "$file_name is not a regular file.\n" >> /dev/stderr
    exit 65
fi

head -n 5 $file_name

printf "Enter a string to search for in $file_name: "
read key

if [ -z "$key" ]; then
    printf "Search string cannot be empty.\n" >> /dev/stderr
    exit 65
fi

fgrep $key $file_name