Delete unimportant text from file in dash

Question

I have a file with too many lines.

Its constructed like:

Text
Text
Text

<--!Important Text begins here-->
important Text
Important Text
Important Text

<--!Important Text ends here -->

Unimportant Text
....

<--!Important Text begins here-->
important Text
Important Text
Important Text

<--!Important Text ends here -->

Unimportant Text
....<--!Important Text begins here-->
important Text
Important Text
Important Text

<--!Important Text ends here -->

Unimportant Text
....

and so on.

How can i take the important part and save it in a new file? I am using the dash terminal from Macintosh

@user3352472 Does these `<--!Important Text ends here -->` markers exists? — jaypal singh, Feb 25 '14 at 20:08
yes, < --!Important Text starts here--> and <--!Important Text ends here --> exist and are equal in the file. They exist about 800 times in the file — user3352472, Feb 25 '14 at 20:14

score 1 · Answer 1 · answered Feb 25 '14 at 20:04

1

Try the following:

sed -n '/<--!Important Text begins here-->/,/<--!Important Text ends here -->/ p' \
  infile | 
  fgrep -v -e '<--!Important Text begins here-->' \
           -e '<--!Important Text ends here -->' \
   > outfile

Note: Assumes that all <--!Important Text ... markers are on a separate line each.

answered Feb 25 '14 at 20:04

mklement0

382,024
64
607
775

fgrep: -e: No such file or directory fgrep: : No such file or directory fgrep: : No such file or directory sed: RE error: illegal byte sequence – user3352472 Feb 26 '14 at 10:13
@user3352472: Tell me what you get when you run `fgrep --version` - while you're at it, als run `sed --version` and `awk --version`; I'm unclear what you mean by "dash terminal" - if by "dash" you mean the [dash shell](http://en.wikipedia.org/wiki/Debian_Almquist_shell), that would be surprising; that said, it's not the _shell_ that matters here, but what versions of the _command-line tools_ you're running. – mklement0 Feb 26 '14 at 16:58

score 1 · Accepted Answer · edited Feb 25 '14 at 21:28

1

If you wish to include the markers then you can do something like:

awk '/<--!Important Text begins here-->/,/<--!Important Text ends here -->/' file

If you wish to ignore the markers and just print the content between them, you can do:

awk '
/<--!Important Text begins here-->/{p=1; next}
/<--!Important Text ends here -->/{p=0}
p' file

The first solution is a regex range. It tells awk to print everything between the range (inclusive). To ignore the markers, you just need to set and unset the flag.

edited Feb 25 '14 at 21:28

mklement0

382,024
64
607
775

answered Feb 25 '14 at 20:34

jaypal singh

74,723
23
102
147

i tried both and directed the output into a file but the file is empty. – user3352472 Feb 26 '14 at 10:18

Delete unimportant text from file in dash

2 Answers2