[SOLVED] How to replace "-\n>" to "->" in linux using sed

Asoo · 04-19-2017, 07:46 AM

Hi,

I would like to do the following:

Code:

123456-
>123456

to

Code:

123456->123456

I would like to replace "\n" between "-" and ">" to be replaced by none.

As I have other "\n" that should be unchanged.

Thanks!

syg00 · 04-19-2017, 08:03 AM

And your attempts have been what ?. If you've made no effort, why should we do it for you ?.
sed has the commands to do this - well documented.

Asoo · 04-19-2017, 08:23 AM

I have done few attempts. But I didn't wrote it here because none of it worked.

I wrote this (which are obviously not correct):

head abc.txt | sed 's/-\n\>/-\>/g'

head abc.txt | sed 's/-\n>/->/g'

head abc.txt | sed 's/-\\n\>/-\>/g'

I am confused because when I wanted to enter "\n" between line, it is done quite easily by replacing ">" to ">\n" but reverse of it doesn't apply. That's why I am stuck.

kakistocrat · 04-19-2017, 08:34 AM

It's tricky to get at the new line. Based on the small sample you gave, you could do it by checking for a dash at the end of each line and then, if one is found, appending the next line of input before doing the substitution.

Code:

sed -e '/-$/{ N; s/\n//; }' abc.txt

The /-$/ looks for a dash at the end of a line, then if one is found the N and s/// commands are executed.

Code:

man sed

Asoo · 04-19-2017, 08:46 AM

Thank you so much for the reply!

Yes, it worked. Thanks for the link of manual. (I was also reading it)

syg00 · 04-19-2017, 08:27 PM

Quote:

Originally Posted by Asoo

I am confused because when I wanted to enter "\n" between line, it is done quite easily by replacing ">" to ">\n" but reverse of it doesn't apply. That's why I am stuck.

sed is stream oriented, so it gives you a record at a time - up to, but not including, the newline. Hence your problems. The solution provided is a simple way to overcome this if the data structure is known in advance.