Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

Linux command  'comm' and whitespace

Posted on 2014-11-20
2
Medium Priority
?
389 Views
Last Modified: 2014-11-22
I am seeing every single line show up on my comm comparison, because one file uses spaces, while the other uses tabs

Is there any way to get comm to print out the differences that exclude white space ?

Thanks
0
Comment
Question by:Anthony Lucia
  • 2
2 Comments
 
LVL 68

Expert Comment

by:woolmilkporc
ID: 40455791
Alas, "comm" does not have such an option.

"diff" on the other hand, does have options for this, "-w" to ignore all whitespace and "-b" to ignore changes in the number of whitespaces.

diff -w a.conf b.conf

If you don't want to see the additional info which "diff" provides but only the changes:

diff -w a.conf b.conf | grep -E "^<|^>"

If you don't want to see the additional info which "diff" provides and finally filter out the "<" and ">" characters:

diff -w a.conf b.conf | grep "^<" | cut -f2- -d" "
(differences in file 1)

diff -w a.conf b.conf | grep "^>" | cut -f2- -d" "
(differences in file 2)

diff -w a.conf b.conf | grep -E "^<|^>" | cut -f2- -d" "
(all differences)
0
 
LVL 68

Accepted Solution

by:
woolmilkporc earned 2000 total points
ID: 40455804
To work with "comm" nevertheless you could delete all whitespace before comparing:

sort b.conf | tr -d " \t" > b.conf.sorted
sort a.conf | tr -d " \t" | comm -2 -3 - b.conf.sorted
rm b.conf.sorted

Instead of " \t" you can use the "[:blank:]" character class.

The drawback with all of the above is that the final output will also lack the whitespaces.
0

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

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

If you have a server on collocation with the super-fast CPU, that doesn't mean that you get it running at full power. Here is a preamble. When doing inventory of Linux servers, that I'm administering, I've found that some of them are running on l…
SSH (Secure Shell) - Tips and Tricks As you all know SSH(Secure Shell) is a network protocol, which we use to access/transfer files securely between two networked devices. SSH was actually designed as a replacement for insecure protocols that sen…
Learn several ways to interact with files and get file information from the bash shell. ls lists the contents of a directory: Using the -a flag displays hidden files: Using the -l flag formats the output in a long list: The file command gives us mor…
How to Install VMware Tools in Red Hat Enterprise Linux 6.4 (RHEL 6.4) Step-by-Step Tutorial
Suggested Courses
Course of the Month8 days, 11 hours left to enroll

877 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