for loop

surferdude · 07-26-2012, 05:56 AM

Hi Guys and Girls

I'm trying to do a for loop....

OSNAME="Gentoo 2012 CentOS 5.4 Windows 7 Professional"

for OS in $OSNAME
do
echo "hey" "$OS"
done

The output looks like...

hey Gentoo
hey 2012
hey CentOS
hey 5.4
hey Windows
hey 7
hey Professional

What I want it to look like is...

Hey Gentoo 2012
Hey CentOS 5.4
Hey Windows 7 Professional

How can I do this?

I can put something at the end of each OS name like Gentoo 2012bb CentOS 5.4bb. Make sense?

surferdude

NevemTeve · 07-26-2012, 06:12 AM

Code:

OSNAME=("Gentoo 2012", "CentOS 5.4", "Windows 7 Professional")
for OS in "${OSNAME[@]}"; do echo "hey" "$OS"; done

_val_ · 07-26-2012, 06:49 AM

Another aproach

Code:

#!/bin/bash

oses=( Fedora, "Red Hat", "Debian", "Arch Linux", Windows )
echo -ne "There are ${#oses[@]} Operating Systems Availiable"
echo
for os in "${!oses[@]}"; do printf '%s\n' " MyOS ${oses[os]}"; done

Reuti · 07-27-2012, 06:54 AM

Don’t use commas, they will be part of the string. Each word is just assigned to one field in the array.

_val_ · 07-27-2012, 07:20 AM

Quote:

Originally Posted by Reuti

Don’t use commas, they will be part of the string. Each word is just assigned to one field in the array.

Totally agree with you. Comma's are not needed. Probably a bad habbit from other prog/script languages.

David the H. · 07-27-2012, 12:27 PM

Please use ***[code][/code] tags*** around your code and data, to preserve formatting and to improve readability. Please do not use quote tags, bolding, colors, or other fancy formatting.

It's vital in scripting to understand how the shell handles arguments and whitespace:
http://mywiki.wooledge.org/Arguments
http://mywiki.wooledge.org/WordSplitting
http://mywiki.wooledge.org/Quotes

A for loop processes one "word" at a time. When you expand the variable, it gets broken into words based on whitespace. Unless you quote it, in which case the whole string gets treated as a single word.

http://wiki.bash-hackers.org/syntax/ccmd/classic_for
Don't Read Lines With For

This is why you should never store lists of things in a single variable. That's what arrays are for.

The above posts show generally how to do it, but see here for more details:

http://mywiki.wooledge.org/BashFAQ/005

Finally though, for the simple requirements listed above, we don't even need a loop, just printf, which has implicit looping built in.

Code:

oses=( "Gentoo 2012" "CentOS 5.4" "Windows 7 Professional" )

printf 'Hey %s\n' "${oses[@]}"