sh /home/ubuntu/Desktop/test.sh -f /home/u/Desktop/ -p 'TEST'

#!/bin/bash

valid=0
file_arg=""
display_help=""
column=""
pattern=""

while getopts f:d:s:m: opt
do
    case "$opt" in
        d)  display_help=$OPTARG
            ;;
        f)  file_arg=$OPTARG
            ;;
        c)  column=$OPTARG
            ;;
        p)  pattern=$OPTARG
            ;;
        *)  valid=1
            break
            ;;
    esac
done

if [ $valid -eq "0" ]
then
    if [ $pattern != "" ]
    then
        cat $file_arg | grep $pattern
    else
        cat $file
    fi
else
    echo -n "Usage: FILE -f <name> | COLUMN -> -c <name> | HELP -> -d | PATTERN -> -p <expression>"
fi

#!/bin/bash

# switch around valid, convention is 1 == true and 0 == false
valid=1
file_arg=""
display_help=""
column=""
pattern=""

# getopt patterns need to match following case statement
while getopts f:d:c:p: opt;
do
    case $opt in
        d)  display_help=$OPTARG
            ;;
        f)  file_arg=$OPTARG
            ;;
        c)  column=$OPTARG
            ;;
        p)  pattern=$OPTARG
            ;;
        *)  valid=0
            break
            ;;
    esac
done

# changed value to reflect true false convention
if [ "$valid" -eq "1" ]
then
    # string comparison in bash should be done using specific operators
    if [ -n "$pattern" ]
    then
        cat $file_arg | grep $pattern
    else
        # typo, this should be file_arg?
        cat $file_arg
    fi
else
    echo -n "Usage: FILE -f <name> | COLUMN -> -c <name> | HELP -> -d | PATTERN -> -p <expression>"
fi