Simulating Word Wrap with "probably" SED

fsenes · 05-05-2007, 10:11 AM

Hi
I need a SED line to insert \n (newline) after nth character of a line.

My goal is to simulate word wrap.

Suppose that I have a line like this:

You should include as much detail as possible in your message, including exact error messages (where applicable) and what you have done so far.

I want it as follows:

You should include as much detail as possible (\n)
in your message, including exact error messages (\n)
(where applicable) and what you have done so far. (\n)

In this example the sum of characters for each line is 50

Appreciate very much any help
Best

homey · 05-05-2007, 12:43 PM

Maybe something like this...

Code:

sed -e 's/.\{45\} /&\n/g' file.txt

fsenes · 05-06-2007, 01:11 AM

Quote:

Originally Posted by homey

Maybe something like this...

Code:

sed -e 's/.\{45\} /&\n/g' file.txt

Worked near to perfect
But may not work if the word containing the 45th chr is very long. Therefore counting 50 chars than returning to the last occurance of "SPACE" or;
replacing the occurance closest (but before) to 50th chr of "SPACE" with "NEWLINE" may handle the problem better I think.

Thks anyway indeed

A.Thyssen · 03-02-2009, 07:50 PM

Quote:

Originally Posted by homey

Maybe something like this...

Code:

sed -e 's/.\{45\} /&\n/g' file.txt

That is very near perfect for a sed text word-wrap formater..

However \n does not work on all sed's and it will stuff up for input already with some extra spacing and line formating.

here is my final solution...

For sanitized text (like a column of words, as in the output of a piped 'ls')

Code:

tr '\012' ' ' |
  sed 's/ $/@/; s/[^@]\{55\} /&@/g' |
    tr '@' '\012'

feed the output of 'ls' to it to test...

For unsanatized blank line separated paragraphs,

Code:

tr -s ' ' ' ' | tr '\012' ' ' |
  sed 's/ $/@/; s/   */@@/g; s/[^@]\{55\} /&@/g' |
    tr '@' '\012'

try feeding a 'ls -C' output to this!!!

The sanatization can still be improved... any takers?

gmendoza · 04-15-2009, 05:38 PM

Quote:

Originally Posted by fsenes

My goal is to simulate word wrap.

Suppose that I have a line like this:

You should include as much detail as possible in your message, including exact error messages (where applicable) and what you have done so far.

I want it as follows:

You should include as much detail as possible (\n)
in your message, including exact error messages (\n)
(where applicable) and what you have done so far. (\n)

In this example the sum of characters for each line is 50

Appreciate very much any help
Best

You may be interested in the "fold" command, which is included with almost any GNU system.

Code:

fold -s -w 50 textfile.txt

This would wrap at 50 characters, but only at spaces, so as not to chop words in the middle.

See "man fold" for more info.

Regards

Gilbert

A.Thyssen · 04-16-2009, 12:24 AM

The "fold" command is good, but it only breaks long lines.

If you are going to use a linux command, the better one is "fmt" which has options to fill-out short lines, specify margins, and prefix strings, and also remove extra spaces between words.

Basically it can do what "fold" does, and more.

Another similar program that does not seem to have gained the popularity it deserves is "par"
http://en.wikipedia.org/wiki/Par_(command)
http://www.nicemice.net/par/

The nice thing about "par" is it understands and preserves things like C-comments, and Mail Quotation indenting characters.

Unfortunately it isn't readily available in linux repositories, and its documentation is bad, though the command itself is simple.

gmendoza · 04-16-2009, 01:43 AM

Quote:

Originally Posted by A.Thyssen

The "fold" command is good, but it only breaks long lines.

If you are going to use a linux command, the better one is "fmt" which has options to fill-out short lines, specify margins, and prefix strings, and also remove extra spaces between words.

Basically it can do what "fold" does, and more.

Oooo... now fmt is cool. I really like the filling out of short lines, and uniformed spacing. Interestingly, it won't add an extra space between sentences that only have one space, however it does remove extra spaces between sentences nicely. I can think of an easy sed command to fix the former, anyway. Great suggestion, thanks!

Quote:

Originally Posted by A.Thyssen

Another similar program that does not seem to have gained the popularity it deserves is "par"
http://en.wikipedia.org/wiki/Par_(command)
http://www.nicemice.net/par/

I came across par a while back, and it appears the documentation hasn't improved at all since then.