Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Understanding pattern matching used in a grep command
Top Forums Shell Programming and Scripting Understanding pattern matching used in a grep command Post 302605189 by kristinu on Tuesday 6th of March 2012 09:26:20 PM
Old 03-06-2012
The thing is that if I bracket --help, grep does not run the --help command line option.
Code:
echo "--help" | grep -iE '(--help)'

But doing
Code:
echo "--help" | grep -iE '--help'

does run the help option of grep.

Using the brackets did not require use of [-]- or -- in front of the pattern.

Correct me if I am wrong on the following:

In the regular expression [-]-help, the - inside the square brackets matches a character set which contains a single character ( - in this case) and the literal string "-help".
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

perl pattern matching vs. grep

I originally had a shell script that did a grep 10 times to pull out the number of times a certain pattern occured in a file: ie... aOccurances=`grep aPattern file|wc -l` bOccurances=`grep bPattern file|wc -l` ... ... ... fOccurances=`grep fPattern file|wc -l` As the file got bigger with... (0 Replies)
Discussion started by: junkmail426
0 Replies

2. Shell Programming and Scripting

using command line arguments as columns for pattern matching using awk

Hi, I wish to use a column, as inputted by a user from command line, for pattern matching. awk file: { if($1 ~ /^8/) { print $0> "temp2.csv" } } something like this, but i want '$1' to be any column as selected by the user from command line. ... (1 Reply)
Discussion started by: invinclible0009
1 Replies

3. AIX

matching pattern in 'ps' command

Hi all, I have two instance of jboss (jboss and jboss2). In a shell script that I am writing, I need to grep for each instance of jboss. If i use ps -ef|grep 'jboss', it will also return the process for my second instance of jboss, which is jboss2. Can someone tell me how can i specify the... (1 Reply)
Discussion started by: haroon_a
1 Replies

4. UNIX for Dummies Questions & Answers

grep only word matching the pattern

Hi gurus, A file contains many words in format "ABC.XXXX.XXXX.X.GET.LOG" (X->varying). Now my shell script want this list (only words in formatABC.XXXX.XXXX.X.GET.LOG ) to continue the process. Pls help me. Thanks, Poova. (8 Replies)
Discussion started by: poova
8 Replies

5. UNIX for Dummies Questions & Answers

Issues while pattern matching using grep

Hi, I have a file f1 wi the following data f1.txt ======== Report ID Report Name ----------------------------------------------------------------- Post Requests : 2 Post successes : 2 ============================================= I need to search for the... (2 Replies)
Discussion started by: RP09
2 Replies

6. UNIX for Dummies Questions & Answers

Grep -v lines starting with pattern 1 and not matching pattern 2

Hi all! Thanks for taking the time to view this! I want to grep out all lines of a file that starts with pattern 1 but also does not match with the second pattern. Example: Drink a soda Eat a banana Eat multiple bananas Drink an apple juice Eat an apple Eat multiple apples I... (8 Replies)
Discussion started by: demmel
8 Replies

7. Shell Programming and Scripting

Grep log file to get line above matching pattern

Hi, I have a log file that looks like this "delete" : { "_type" : "cl", "_id" : "1000600000000562636", "_version" : 1, "status" : 200, "found" : false } }, { "delete" : { "_type" : "cl", "_id" : "1000600000000562643", ... (4 Replies)
Discussion started by: wahi80
4 Replies

8. Shell Programming and Scripting

UNIX command to get the latest file and also matching pattern

we want to fetch the latest file in a given directory and also the file name should match the below pattern Example file name ->hrdata-2015-10-13-16-45-26.xml(2015-10-13-16-45-26- it is not current timestamp, we just need to check for the pattern) We expect the file will have the... (3 Replies)
Discussion started by: vishwanath001
3 Replies

9. UNIX for Beginners Questions & Answers

Grep file starting from pattern matching line

I have a file with a list of references towards the end and want to apply a grep for some string. text .... @unnumbered References @sp 1 @paragraphindent 0 2017. @strong{Chalenski, D.A.}; Wang, K.; Tatanova, Maria; Lopez, Jorge L.; Hatchell, P.; Dutta, P.; @strong{Small airgun... (1 Reply)
Discussion started by: kristinu
1 Replies

10. Shell Programming and Scripting

Expect pattern matching in the command output

This is the command output need to be matched: Telnet console listening to port 42365. (the port number changes every time) Code to test it: ======================================= #!/tools/AGRtools/bin/expect exp_internal 1 set timeout 10 spawn bash set bashId $spawn_id ... (4 Replies)
Discussion started by: marsala
4 Replies

LEARN ABOUT BSD

zgrep

ZGREP(1)						      General Commands Manual							  ZGREP(1)

NAME

       zgrep - search possibly compressed files for a regular expression

SYNOPSIS

       zgrep [ grep_options ] [ -e ] pattern filename...

DESCRIPTION

       Zgrep  invokes  grep  on  compressed  or  gzipped  files.   These  grep	options  will  cause  zgrep  to  terminate  with  an  error  code:
       (-[drRzZ]|--di*|--exc*|--inc*|--rec*|--nu*).  All other options specified are passed directly to grep.  If no file is specified,  then  the
       standard input is decompressed if necessary and fed to grep.  Otherwise the given files are uncompressed if necessary and fed to grep.

       If the GREP environment variable is set, zgrep uses it as the grep program to be invoked.

EXIT CODE

       2 - An option that is not supported was specified.

AUTHOR

       Charles Levert (charles@comm.polymtl.ca)

SEE ALSO

       grep(1), gzexe(1), gzip(1), zdiff(1), zforce(1), zmore(1), znew(1)

																	  ZGREP(1)
All times are GMT -4. The time now is 08:38 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy