?
Solved

grep

Posted on 2003-11-13
6
Medium Priority
?
470 Views
Last Modified: 2010-04-21
I have this as my file (myfile) contents
myfile
====
aaaa
bbbb
cccc
dddd

Then i do this
  grep "*a" myfile
but then i still get all the lines! I wished to get the first line only.

How can that be?
0
Comment
Question by:cutie2000
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 2
6 Comments
 

Author Comment

by:cutie2000
ID: 9738659
a good tutorial on grep regular expressions would be good.
0
 
LVL 45

Expert Comment

by:sunnycoder
ID: 9738676
Hi cutie2000,

in grep regex * means 0 or more instances ... thus everything qualifies....
read grep man page... the regex in grep are slightly different from shell regex

to get only first line, use
grep aaaa myfile   :D

Cheers!
Sunny:o)
0
 
LVL 45

Expert Comment

by:sunnycoder
ID: 9738680
0
Get MySQL database support online, now!

At Percona’s web store you can order your MySQL database support needs in minutes. No hassles, no fuss, just pick and click. Pay online with a credit card.

 

Author Comment

by:cutie2000
ID: 9739160
then wouldn't * be useless since it does not perform any grep?
0
 
LVL 45

Accepted Solution

by:
sunnycoder earned 100 total points
ID: 9739191
no... it has its own use, how it behaves depends on how you use ;o) ...I suggest you look at the man page and tutorial carefully ... here is an example from the tutorial

Examples: Wildcards
The File for These Examples
>cat file
big
bad bug
bag
bigger
boogy

 Wildcards #1
>grep "b.*g" file
big
bad bug
bag
bigger
boogy

 Wildcards #2
>grep "b.*g." file
bigger
boogy

 Wildcards #3
>grep "ggg*" file
bigger

 
0
 
LVL 3

Assisted Solution

by:Ravi Goru
Ravi Goru earned 100 total points
ID: 9872626
0

Featured Post

Free Tool: ZipGrep

ZipGrep is a utility that can list and search zip (.war, .ear, .jar, etc) archives for text patterns, without the need to extract the archive's contents.

One of a set of tools we're offering as a way to say 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

How many times have you wanted to quickly do the same thing to a list but found yourself typing it again and again? I first figured out a small time saver with the up arrow to recall the last command but that can only get you so far if you have a bi…
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…
Get a first impression of how PRTG looks and learn how it works.   This video is a short introduction to PRTG, as an initial overview or as a quick start for new PRTG users.
How to Install VMware Tools in Red Hat Enterprise Linux 6.4 (RHEL 6.4) Step-by-Step Tutorial
Suggested Courses
Course of the Month11 days, 22 hours left to enroll

752 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