Script not working the way I programmed it to

scandalist · 06-06-2012, 12:45 AM

I want to read user input and write to a file with bash but this is not working for some reason. The script executes but nothing happens upon my input.

Code:

#!/bin/bash

networking() {

echo "Press 1 to write to /etc/network/interfaces"

read choice

if [ choice = 1 ]



then

echo auto eth0 > /etc/network/interfaces
echo address 192.168.1.122 >> /etc/network/interfaces

fi

}

networking;

evo2 · 06-06-2012, 12:51 AM

Hi,

Code:

if [ "$choice" = "1" ]

Evo2.

PS. Others may also post and tell you to use [[ and ]] instead of [ and ] and also to use == instead of =. While that advice might be good practice for bash, it is not required to get your script working.

Didier Spaier · 06-06-2012, 12:55 AM

Bash works with strings I think and choice is a variable thus write:

Code:

 if [ $choice = "1" ]

Sorry, too late...

scandalist · 06-06-2012, 01:00 AM

Wow, quick reply. Its doing what I want it to now, funny how every example I found online excluded that formatting. Thank you!

pan64 · 06-06-2012, 01:08 AM

Quote:

Originally Posted by evo2

PS. Others may also post and tell you to use [[ and ]] instead of [ and ] and also to use == instead of =. While that advice might be good practice for bash, it is not required to get your script working.

Also you do not need " around 1: [ "$choice" = 1 ] is sufficient.

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evo2 · 06-06-2012, 01:23 AM

Quote:

Originally Posted by pan64

Also you do not need " around 1: [ "$choice" = 1 ] is sufficient.

True, but it's portable.

Evo2.

bigearsbilly · 06-06-2012, 01:31 AM

also you might find it slicker to use the select statement in bash.

David the H. · 06-06-2012, 11:46 AM

In square-bracket shell tests "=,<,>," are string comparators. For integers, you need to use "-eq,-lt,-gt,-le,-ge".

Also, when using bash or ksh, it's recommended to use [[..]] for string/file tests, and ((..)) for numerical tests. Avoid using the old [..] test unless you specifically need POSIX-style portability.

http://mywiki.wooledge.org/ArithmeticExpression
http://mywiki.wooledge.org/BashFAQ/031
http://wiki.bash-hackers.org/commands/classictest
http://wiki.bash-hackers.org/syntax/...nal_expression

And if I may offer another bit of advice, clean, consistent formatting makes code readable and more easily debuggable. Indent all your sub-commands, and separate logical sections with whitespace. Add comments anywhere the code isn't completely obvious (and remember, what seems obvious to you now will not be so a year or so down the line).

Many people also feel that it's more readable to place the "do/then" keywords on the same line as the "for/while/until/if" keywords, as it more clearly separates the outside block from the inside block. Example:

Code:

for var in fee fai foo fum ; do

	if [[ "$var" == "foo" ]]; then
		echo "Found 'foo'."
	fi

done