question on vi

[Igor Sovin]

Hi!
I need to make a script in which I must substitute some symbols, after "if else" construction.
For example I need to change all "a" symbols to "b".
Is it possible to make it using vi, so then I can start my script from command line?
#./myscript

[Mic V. · Accepted solution]

Igor,

Sorry, I'm a little unclear on the question. Are you trying to run "myscript", which opens another file "myfile" and changes all "a" to "b"?

In vi:

:1,$s/a/b/g

In sed:

sed "s/a/b/g"

Perl is a nice language for string manipulation -- better IMO than shells or vi.

HTH,
Mic

[Igor Sovin]

Hi!

thank you!
And how to do the same thing in one file?

Here is the example of myscript:

#!/usr/bin/sh
HM=$(hostname)
then I have some commands operating with hostnames, and I need to change hostnames to $HM.
To do that I have to press ":" in command mode and then type what you said. But I need to that automaticly by running myscript.
Is it possible?
I think that only sed is able to do it.

[Biswajit Tripathy]

Igor wrote:
> To do that I have to press ":" in command
> mode and then type what you said. But I need
> to that automaticly by running myscript.
> Is it possible?
> I think that only sed is able to do it.

Yes, you need to use sed. Use following command
in your script:

cat old_file | sed "s/old_hostname/$HN/g" > new_file

The old_file is the name of the file with old
hostname and new_file is exactly same as old file
with hostname changed to whatever string $HN set
to.

- Biswajit

[Nguyen Anh Tien]

Read my attached file Vi Pages - Substitution Guide .
HTH
tienna