I am trying to write a shell script that will allow the typing of a value, then using that value to replace data in a text file.
I suspect I need sed.

The format of the file is:
Variable1:Value1
Variable2:Value2

The interaction would be something like:
Shell Prompt: "Please enter the value for Variable1: "
User enters: "NewValue"

at which point I'd need to search the text file for Variable1:<ANYTHING> and replace it with Variable1:NewValue

I am barely knowledgeable in sed and RegEx. I tried looking through Sed - An Introduction and Tutorial but I think I'm not quite at that level yet.

Any help is welcome!

Thanks,
Alex

the logic you can use in your script is as folloes :

%s/oldword/newword/g

You can take the newword and oldword as input from screen and pass them into ur script.

hope I have made myself clear

please revert back in case you need any more help ..

Thanks and Regards

Ultimatix.

for getting the new variable use code

====================
echo "Please enter the value for Variable1: \c"
read newvar
if [ -z "$newvar" ];then
echo " NO INPUT DETECTED"
else
echo " going to replace $variable1 with $newvar"
# here you can have your code to replace the old variable with $newvar

Wow, thank you both for such fast responses.

That is a great help, but my only remaining problem is that I don't know what will come after Variable1:, Variable2:, etc
They may have already run this previously so now rather than:
Variable1:Value1
Variable2:Value2

it could read:
Variable1:NewValue
Variable1:SomeOtherValue

How could I search for a known beginning and replace the whole line with that same beginning followed by a new value?

Thanks again,
Alex

Something like this?

read newvar1
read newvar2

sed -e "s/Variable1:/Variable1:$newvar1/" -e "s/Variable2:/Variable2:$newvar2/" file > newfile
mv newfile > file

Regards

That's not working for me. Here are some specifics:

Existing line:
smtpDestination:=125

Command Run:
sed -e "s/smtpDestination:=/smtpDestination:=localhost:25/" alex.cfg > alex2.cfg

New Line:
smtpDestination:=localhost:25125

It's inserting the localhost:25, rather than replacing the line.

Thanks,
Alex

sed -e "s/smtpDestination:=.*/smtpDestination:=localhost:25/" alex.cfg > alex2.cfg

Perfect! Thanks everyone!

Last question I promise. How can I read and extract the existing data so I can show it to the user before they change it?

So for example, how would I extract
localhost:25
from
smtpDestination:=localhost:25

Thanks for all your help everyone!

Alex

sed -e "s/smtpDestination:=\(.*\)/\1/" alex.cfg

It's not quite right I think - it's printing out the whole alex.cfg.

My script looks like this:

Am I doing something wrong?

Thanks,
Alex