Sponsored Content
Full Discussion: Avoiding external utilities
Top Forums Shell Programming and Scripting Avoiding external utilities Post 303010825 by rovf on Monday 8th of January 2018 05:42:18 AM
Old 01-08-2018
Well, first to the usage of fgrep: I don't think you will notice any time different to egrep. The main advantage of fgrep is not speed, but convenience: With fgrep, you don't have to escape characters which have a special meaning inside a regexp.

Also, note that egrep and fgrep are obsolete; the recommended form is
Code:
grep -E

and
Code:
grep -F

. Of course, especially when typing from the command line, fgrep is faster to type than grep -F.

Not to the problem at hand: While I don't see how you can avoid an external utility (unless you write your own shell version of grep, which is possible, but not necessarily faster when it comes to large input), you can - if you are using bash or zsh - at least get rid of the pipe:

Code:
grep -F  'i am on the first line'  <<<$MASSIVETEXT

 

9 More Discussions You Might Find Interesting

1. SCO

Avoiding duplicates with some special case

Hi Gurus, I had a question regarding avoiding duplicates.i have a file abc.txt abc.txt ------- READER_1_1_1> HIER_28056 XML Reader: Error occurred while parsing:; line number ; column number READER_1_3_1> Sun Mar 23 23:52:48 2008 READER_1_3_1> HIER_28056 XML Reader: Error occurred while... (0 Replies)
Discussion started by: pssandeep
0 Replies

2. OS X (Apple)

Installing applications by avoiding GUI

Hi Experts, Now the problem is when I run the install script inside .app folder, it opens a GUI and asks for user input. I want to avoid these GUI. I want to provide input when i run install script e.g. $ ./install < inputfile I used to redirect input from input file to install script. But... (4 Replies)
Discussion started by: akash.mahakode
4 Replies

3. Shell Programming and Scripting

using find but avoiding sparse files

I am no Unix administrator...I live in windows land. I wrote a script to find files of certain names and process them but was later advised to avoid checking sparse files since it would use up a lot of resources and the files I was looking for were not there. How do I avoid doing the find on... (3 Replies)
Discussion started by: shellFun
3 Replies

4. UNIX for Dummies Questions & Answers

Avoiding the second run of the script

Hi all, I want to put a check in my script to check if the same instance is already running and not finished and if not then does not allow it to run! in which part of my script I should put this? and any idea how I should write it? tx (4 Replies)
Discussion started by: messi777
4 Replies

5. Shell Programming and Scripting

Avoiding 'sh -c' when running ps from CRON

Hi, I have a script which has the below line: ps -ef | grep ${SCRIPT_NAME} | grep ksh | grep -v grep >> /tmp/instance.tmp When the script is invoked through CRON, I get 2 lines in instance.tmp when actually only one instance is running: cdrd 17790 17789 0 15:14:01 ? 0:00 /bin/ksh... (8 Replies)
Discussion started by: cavallino4u
8 Replies

6. UNIX for Dummies Questions & Answers

Avoiding the history

In bash shell, how we can avoid the commands getting recorded in history file. One way i can think of is : export HISTSIZE=0 Is there any other way to achieve this? Thanks (1 Reply)
Discussion started by: pandeesh
1 Replies

7. Shell Programming and Scripting

Avoiding some files inside a loop

In my script I need to loop around some files like below example files are fa.info.abcd fa.info.bxde fa.info.cdas ------ for test_data in fa.info.* do # Some text appending logic applied # Copy to another directory done Now I need to discard some files while looping around ... (9 Replies)
Discussion started by: smile689
9 Replies

8. Shell Programming and Scripting

Search avoiding special characters

Hi all, I have a list which I want to search in another file. I can do that using grep -f but the search is failing due to special characters, how do I solve this? One row in that list is amino-acid permease inda1 gb|EDU41782.1| amino-acid permease inda1 Input file to be searched... (2 Replies)
Discussion started by: gina.lizar
2 Replies

9. Shell Programming and Scripting

Avoiding new line for the counts

Hi Team, Am getting the below output but need the count of records to be displayed in same line but currently count alone moves to next line. Please let me know how we can still keep the count in the same line. ######code ##### while read YEAR; do for i in TEST_*PGYR${YEAR}_${DT}.csv; do... (3 Replies)
Discussion started by: weknowd
3 Replies
GZGREP(1)						      General Commands Manual							 GZGREP(1)

NAME
gzgrep, gzegrep, gzfgrep - search possibly compressed files for a regular expression SYNOPSIS
gzgrep [ grep_options ] [ -e ] pattern filename... DESCRIPTION
gzgrep is used to invoke the grep on compress'ed or gzip'ed files. All options specified are passed directly to grep. If no file is speci- fied, 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 gzgrep is invoked as gzegrep or gzfgrep then egrep or fgrep is used instead of grep. If the GREP environment variable is set, gzgrep uses it as the grep program to be invoked. For example: for sh: GREP=fgrep gzgrep string files for csh: (setenv GREP fgrep; gzgrep string files) AUTHOR
Charles Levert (charles@comm.polymtl.ca) SEE ALSO
grep(1), egrep(1), fgrep(1), gzdiff(1), gzmore(1), gznew(1), gzforce(1), gzip(1), gzexe(1) ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +--------------------+-----------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +--------------------+-----------------+ |Availability | SUNWgzip | +--------------------+-----------------+ |Interface Stability | External | +--------------------+-----------------+ NOTES
Source for gzip is available in the SUNWgzipS package. GZGREP(1)
All times are GMT -4. The time now is 04:19 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy