Shell Script Question

[PriusDriver07]

Hello Master Scripters,
I am in scripting nursery and I am trying to write a script that will replace string a with string b. I can get my script to replace single strings with no problem, my issue arrives when one of my strings has two words. I am pretty sure that there are quotes involved for this. Now, can the quotes be in the script instead of being written in the command line. If I run my script with the quotes in the command line the script works perfectly.

My script currently looks like this:

#!/bin/csh
set stringa=$1
set stringb=$2
set filename=$3
sed s/$stringa/$stringb/g $filename

I have tried to run it with

set "stringa"=$1

, but this gives me a syntax error.
I have tried to run it with

set stringa="$1"

, and this seems to have the same effect as no quotes.
I tried also to run it with everything above the sed line without quotes and then the

sed s/"$stringa/"$stringb"/g $filename

, with no luck.

Any other suggestion on how to accomplish this task?

[Infarction]

what about sed "s/$stringa/$stringb/g" $filename ?

[pheeror]

use -i parameter for sed
#i'm not csh user
sed -i "s/$stringa/$stringb/g" $filename
#and test if you have to make quoutes around $filename to
#if it doesn't help, try echo $stringa and $stringb before sed

[PriusDriver07]

what about sed "s/$stringa/$stringb/g" $filename ?

Negative, That didnt work wither. Whenever there is a space it takes the next word and puts it in the next available variable.

So, If I want to replace "My House" for Home in file mystory, and i type
$./scriptname My House Home mystory.txt

it sets $1 to "My" $2 to "House" and $3 to "Home", but $3 should be the filename in this case mystory.txt

I need to get it to do take this command:
$./scriptname My House Home mystory.txt

and set $1 to My House, $2 to Home and $3 to mystory.txt. Is this even possible without issuing the command like this:
$./scriptname "My House" Home mystory.txt ?

[PriusDriver07]

use -i parameter for sed
#i'm not csh user
sed -i "s/$stringa/$stringb/g" $filename
#and test if you have to make quoutes around $filename to
#if it doesn't help, try echo $stringa and $stringb before sed

I tried using the sed -i but I think its not an option in csh. I did the echo before sed, and sure enough it is showing the strings all messed up if one string has two or more words.

[Infarction]

You do need the quotes around it. There's no way around that - the shell will automatically break it up into separate parameters. Afterall, there's no way for the shell to know the difference between ./script "My House" Home someFile and ./script My "House Home" someFile without the quotes being there.

And sed -i would not change the result, just the behavior of the substitution (changing the file in place rather than printing the result).