Solved

A little bit of sed/awk magic

Posted on 2011-09-07
5
283 Views
Last Modified: 2012-05-12
Hi guys,

I'm looking for an expert who is familiar with sed and awk, I need to parse a text file using Bash. My text file looks something like this:

; this is a comment

[mapping]

; some more comments here
foo=bar
apple    =   banana

; and more comments
       qwerty=dvorak

[statement]
this is a block of text which should
be read verbatim, without any
; parsing of any kind = that was applied
to the = mapping section 

above.

Open in new window


Basically what I need to do is:

1) In the "[mapping]" section of the file:
    a) Ignore lines that are pure whitespace or that start with a semicolon
    b) Get each mapping pair, e.g. "foo" and "bar", "apple" and "banana" etc
    c) Trim whitespace off the pairs

2) In the "[statement]" section of the file
    a) Get the entire block of text following the line that says [statement], verbatim, without any of the parsing or formatting that was done in the [mapping] section.

I hope this isn't too complicated. It doesn't need to be really robust, the example I gave above is about as bad as the text file will get and it can die horribly if it is malformed. I'm not concerned much with efficiency either (the file I'm parsing is always going to be pretty small), so whatever solution can read the file in over and over again, re-parse things more than it needs to etc.
0
Comment
Question by:Frosty555
  • 3
5 Comments
 
LVL 68

Accepted Solution

by:
woolmilkporc earned 250 total points
ID: 36498730
1)

awk '/\[mapping\]/,/\[statement\]/ {if($0~"=") print $1 $2 $3}' inputfile

2) Where does the [statement] section end?
0
 
LVL 38

Expert Comment

by:wesly_chen
ID: 36499522
A2.
awk 'BEGIN{found=0;} /\[statement\]/ {found=1;} {if(found==1) print}'  /path-to-inputfile | tail -n+2
0
 
LVL 38

Expert Comment

by:wesly_chen
ID: 36499769
Here is another version of A2 by perl command line

perl -ne 'if (/\[statement\]/){$state=1; next;} print if ($state eq 1);'  /path-to-inputfile
0
 
LVL 38

Assisted Solution

by:wesly_chen
wesly_chen earned 250 total points
ID: 36499782
Small modification of awk in #36499522
awk 'BEGIN{found=0;} /\[statement\]/ {found=1;next} {if(found==1) print}'  /path-to-inputfile
0
 
LVL 31

Author Comment

by:Frosty555
ID: 36543381
woolmilkporc:
awk '/\[mapping\]/,/\[statement\]/ {if($0~"=") print $1 $2 $3}' inputfile

Open in new window

This successfully parses out the contents of the [mapping] section.

For your question, the [statement] block ends at the end of the file.

wesly_chen:
awk 'BEGIN{found=0;} /\[statement\]/ {found=1;next} {if(found==1) print}'  /path-to-inputfile

Open in new window

This successfully grabs the [statement] block.

Thanks guys!
0

Featured Post

Announcing the Most Valuable Experts of 2016

MVEs are more concerned with the satisfaction of those they help than with the considerable points they can earn. They are the types of people you feel privileged to call colleagues. Join us in honoring this amazing group of Experts.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Adding more CPU cores to a Linux VM 5 93
VMware Workstation 12 Player 16 71
SIP / Streaming - real time communications testing 8 47
android secure ftp 3 32
Join Greg Farro and Ethan Banks from Packet Pushers (http://packetpushers.net/podcast/podcasts/pq-show-93-smart-network-monitoring-paessler-sponsored/) and Greg Ross from Paessler (https://www.paessler.com/prtg) for a discussion about smart network …
Google Drive is extremely cheap offsite storage, and it's even possible to get extra storage for free for two years.  You can use the free account 15GB, and if you have an Android device..when you install Google Drive for the first time it will give…
Learn how to get help with Linux/Unix bash shell commands. Use help to read help documents for built in bash shell commands.: Use man to interface with the online reference manuals for shell commands.: Use man to search man pages for unknown command…
Connecting to an Amazon Linux EC2 Instance from Windows Using PuTTY.

813 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

17 Experts available now in Live!

Get 1:1 Help Now