CODEWITHSUNDEEP
bashshellunixscripting
PFKrang
PFKrang

Reputation: 289

Unix How to check if a specific word is entered in as an argument

I'm writing a script in Unix but I need a way to check an argument that is entered in the command line is a specific word.

So if when using the script the user types:

$ ./script hello

my script can tell that "hello" was entered as an argument and can display a message appropriately.

And if the user types something other than "hello" as an argument then my script can display another message.

Thanks.

Upvotes: 0

Views: 2484

Answers (5)

Amir H
Amir H

Reputation: 480

In Bash arguments passed to shell scripts are stored in variables named as follows:

$0 = name of the script.
$1~$n = arguments.
$# = number of arguments.
$* = single string of all arguments: "arg1,arg2,..."

you can simply use if [ $1 == "some string" ]; then ...

Upvotes: 2

Piyush Baijal
Piyush Baijal

Reputation: 281

If you are sure about the position of the argument you can :

#!/bin/bash if [[ $1 == SearchWord]];then echo "SearchWord was entered" else echo "SearchWord wasn't entered" fi

Incase you are not sure:

You can use $* 

[ `echo $* | grep $SearchWord| wc -l` -eq 1 ] && echo "Present"|| echo "Not present"

Upvotes: 0

David C. Rankin
David C. Rankin

Reputation: 84561

There are a number of ways to check positional arguments against a list. When there are a number of items in the list, you can use a case statement instead of a string of if ... elif ... elif ... fi comparisons. The syntax is as follows:

#!/bin/bash

case "$1" in

    "hello" )
        printf "you entered hello\n"
        ;;
    "goodbye" )
        printf "well goodbye to you too\n"
        ;;
    * )
        printf "you entered something I don't understand.\n"
        ;;
esac

exit 0

Output/Use

$ ./caseex.sh hello
you entered hello

$ ./caseex.sh goodbye
well goodbye to you too

$ ./caseex.sh morning
you entered something I don't understand.

Upvotes: 3

Andrew Malta
Andrew Malta

Reputation: 850

You can retrieve the command line arguments with $(number)

for example the first argument would exist at $1 the second at $2 etc.

You can use conditionals in BASH (I assume you are using bash) just like any other language; however the syntax is a bit wonky :). here is a link for you http://tldp.org/LDP/Bash-Beginners-Guide/html/chap_07.html

Upvotes: 0

Jahid
Jahid

Reputation: 22428

This should work:

#!/bin/bash
if [[ $1 == hello ]];then
echo "hello was entered"
else
echo "hello wasn't entered"
fi

Upvotes: 3

Related Questions