[SOLVED] Replace a line using sed

finekevin · 02-09-2012, 10:37 AM

Hi,

Hi Linux Gurus,
I need your help!

1) How do we replace the following link with new timeout value in a file using "sed".

timeout 5 ===> timeout 10

Note: I don't know the space/tab between "timeout" string and the value "5".

I can't key on "timeout" or "5" since the file contains the following timeout string and many 5's.
terminal --timeout=15 serial console

2) How do I add the following string at the end of the file using "sed".
riohdid=0

Thank you,
Kevin

TB0ne · 02-09-2012, 11:40 AM

Quote:

Originally Posted by finekevin

Hi,
Hi Linux Gurus,I need your help!

1) How do we replace the following link with new timeout value in a file using "sed".
timeout 5 ===> timeout 10

Note: I don't know the space/tab between "timeout" string and the value "5". I can't key on "timeout" or "5" since the file contains the following timeout string and many 5's. terminal --timeout=15 serial console

You should find out how many spaces/tabs between, or is it variable, and do you need the output in a static or variable form? You can use

Code:

sed 's/timeout *5/timeout 10/g'

which will replace 'timeout <several spaces>5' with 'timeout 10' (one space). If you need the number of spaces to match/be adjusted, that's different.

Quote:

2) How do I add the following string at the end of the file using "sed".
riohdid=0

Why use sed? Just typing in "echo "riohdid=0 >> <filename>" will put that string at the end of a file.

Satyaveer Arya · 02-09-2012, 11:41 AM

Check out these threads, it may help you:

http://www.linuxquestions.org/questi...t-file-594551/
http://www.unix.com/unix-dummies-que...-new-line.html

finekevin · 02-09-2012, 11:44 AM

Thank you very much!

finekevin · 02-22-2012, 03:04 PM

Quote:

Originally Posted by TB0ne

You should find out how many spaces/tabs between, or is it variable, and do you need the output in a static or variable form? You can use

Code:

sed 's/timeout *5/timeout 10/g'

which will replace 'timeout <several spaces>5' with 'timeout 10' (one space). If you need the number of spaces to match/be adjusted, that's different.

Why use sed? Just typing in "echo "riohdid=0 >> <filename>" will put that string at the end of a file.

The "echo" attaching "^M" end of each line. This is not good, since I am modifying the grub.conf

TB0ne · 02-23-2012, 08:52 AM

Quote:

Originally Posted by finekevin

The "echo" attaching "^M" end of each line. This is not good, since I am modifying the grub.conf

Well, you did not say you were modifying grub.conf, so there's no way we can know. And if there is a ^M, then read the man page on the echo statement. Pay particular attention to the "-n":

Code:

-n     do not output the trailing newline

finekevin · 02-23-2012, 01:14 PM

Quote:

Originally Posted by TB0ne

Well, you did not say you were modifying grub.conf, so there's no way we can know. And if there is a ^M, then read the man page on the echo statement. Pay particular attention to the "-n":

Code:

-n     do not output the trailing newline

It works! Thank you!