topic Re: modify string into file in Operating System - Linux

modify string into file

Tonatiuh — Thu, 06 Oct 2005 16:34:24 GMT

Red Hat Enterprise Linux 3

How can I modify certain string which is into a file? (using just a command line statament).

Re: modify string into file

Ivan Ferreira — Thu, 06 Oct 2005 16:57:05 GMT

You can do it to another file using sed. Like this:

sed s/search_string/replacement_string file

sed s/hello/goodbye myfile > myfile2

You can then rename or move the new file.

Re: modify string into file

Gopi Sekar — Fri, 07 Oct 2005 00:55:50 GMT

use sed or awk command scripts.

you can also do string replacement using perl scripts.

Regards,
Gopi

Re: modify string into file

Muthukumar_5 — Fri, 07 Oct 2005 01:44:10 GMT

You can use perl -pi -e 's///g' . It will automatically update into the same file without any string.

# Example:

file1:

hi
bye

# perl -pi -e 's/hi/first/g' file1

file1:

first
bye

hth.

Re: modify string into file

Guru Dutta — Fri, 07 Oct 2005 06:45:25 GMT

Just an short explanation to Muthukumars reply
perl -pi -e 's///g' .

-p -> assumes the following loop around your script. while (<>) {
# your script goes here
} continue {
print or die "-p destination: $!\n";
}

-i -> specifies that files processed by the <> construct are to be edited in-place

-e -> Specifies a line of script.

More details are in the man page.Hope it helps.

Re: modify string into file

Ivan Ferreira — Fri, 07 Oct 2005 11:27:05 GMT

This may be more difficult but works too, use a script wiht vi.

Create the script called script.vi:

^[:%s/string/replacement_string/g
^[:wq

The ^[: is created pressing CTRL+v and ENTER.

Then run

vi -s script.vi file_to_modify

The modifications will be done directly in the file.