Sponsored Content
Full Discussion: Explanation on egrep
Top Forums UNIX for Dummies Questions & Answers Explanation on egrep Post 302594740 by Skrynesaver on Wednesday 1st of February 2012 05:20:30 AM
Old 02-01-2012
Reqular expressions use the square brackets to indicate a character range, the backslash \ is used to escape the following character, thus preventing the regex engine from interpreting it as the beginning of a range.

If it is not included the grep will fail with an error similar to grep: Unmatched [ or [^.
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

tr explanation please

how does below tr command replace nonletters with newlines? I think I understand tr -cs '\n' part.. but what is A-Za-z\' <--- what is this?? tr -cs A-Za-z\' '\n' | -c --complement -s, --squeeze-repeats replace each input sequence of a repeated character that is... (0 Replies)
Discussion started by: convenientstore
0 Replies

2. Shell Programming and Scripting

tr explanation please

how does below tr command replace nonletters with newlines? I think I understand tr -cs '\n' part.. but what is A-Za-z\' <--- what is this?? tr -cs A-Za-z\' '\n' | -c --complement -s, --squeeze-repeats replace each input sequence of a repeated character that is... (1 Reply)
Discussion started by: convenientstore
1 Replies

3. UNIX and Linux Applications

need explanation

Hi am having a c pgm. It has the include files (unistd.h,sys/types.h,win.h,scr.h,curses.h,stdarg.h and color.h). I don't know the purpose of these include files. will u plz explain me. (1 Reply)
Discussion started by: Mari.kb
1 Replies

4. UNIX for Dummies Questions & Answers

Egrep cheat sheet anywhere? Looking for meaning of egrep -c

Hi I've been searching google and have not found what egrep -c means. Does anyone know where I can get a cheat sheet or what that -c means? thanks, Linda (2 Replies)
Discussion started by: leelm
2 Replies

5. UNIX for Dummies Questions & Answers

search ")" with egrep - egrep: syntax error

Hi Guys, we have a shell script which basically query the Database which retrieves huge data and use the data with "egrep" . Now there is some data which contains characters like "abc)" and the same is used like below : "egrep (.+\|GDPRAB16\|GDPR/11702 96 abc)\|$ temp.txt" now while... (7 Replies)
Discussion started by: sagarjani
7 Replies

6. Shell Programming and Scripting

same action in then as in else: explanation?

in /etc/init.d/networking of an ubuntu computer, I found this code: if ifdown -a --exclude=lo; then log_action_end_msg $? else log_action_end_msg $? fi Shouldn't it be replace by ifdown -a --exclude=lo ... (0 Replies)
Discussion started by: raphinou
0 Replies

7. UNIX for Dummies Questions & Answers

In need of explanation

Its great someone provided this script that strips out a filename and extension but can someone explain how each line works? file1='Jane Mid Doe.txt' newfile='Jane.txt' 1) ext=${file1##*.} 2) filename=${file%%.???} 3) set -- $filename 4) newfile="1.$extension" (1 Reply)
Discussion started by: Lillyt
1 Replies

8. Shell Programming and Scripting

code explanation

Can you please explain the following code plz? my_cd=' ' while getopts :e: OPTION; do case "$OPTION" in e) my_cd ="$OPTARG";; esac done if ; then echo " >>> ERROR - I am wrong" echo " >>> ERROR - Hello" exit 99 fi What I don't understand is what is OPTION or... (3 Replies)
Discussion started by: RubinPat
3 Replies

9. Shell Programming and Scripting

Need explanation

Hi, I need more explination on it, how it works abcd="$(echo "$abcd" | sed 's/ //g')" >> ${LOGFILE} 2>&1 can any one suggest me on this? Rgds, LKR (1 Reply)
Discussion started by: lakshmanraok
1 Replies

10. UNIX for Beginners Questions & Answers

Explanation around "+r" in egrep

Hi, Is anyone able to shed some light on "+r"? I know -r in grep refers to a recursive search - I am curious to know what +r specifies. #show process pidin | utility egrep -e "+r" count 2492 Thanks. (3 Replies)
Discussion started by: sand1234
3 Replies
WILDMAT(3)						     Library Functions Manual							WILDMAT(3)

NAME
wildmat - perform shell-style wildcard matching SYNOPSIS
int wildmat(text, pattern) char *text; char *pattern; DESCRIPTION
Wildmat is part of libinn (3). Wildmat compares the text against the pattern and returns non-zero if the pattern matches the text. The pattern is interpreted according to rules similar to shell filename wildcards, and not as a full regular expression such as those handled by the grep(1) family of programs or the regex(3) or regexp(3) set of routines. The pattern is interpreted as follows: x Turns off the special meaning of x and matches it directly; this is used mostly before a question mark or asterisk, and is not spe- cial inside square brackets. ? Matches any single character. * Matches any sequence of zero or more characters. [x...y] Matches any single character specified by the set x...y. A minus sign may be used to indicate a range of characters. That is, [0-5abc] is a shorthand for [012345abc]. More than one range may appear inside a character set; [0-9a-zA-Z._] matches almost all of the legal characters for a host name. The close bracket, ], may be used if it is the first character in the set. The minus sign, -, may be used if it is either the first or last character in the set. [^x...y] This matches any character not in the set x...y, which is interpreted as described above. For example, [^]-] matches any character other than a close bracket or minus sign. HISTORY
Written by Rich $alz <rsalz@uunet.uu.net> in 1986, and posted to Usenet several times since then, most notably in comp.sources.misc in March, 1991. Lars Mathiesen <thorinn@diku.dk> enhanced the multi-asterisk failure mode in early 1991. Rich and Lars increased the efficiency of star patterns and reposted it to comp.sources.misc in April, 1991. Robert Elz <kre@munnari.oz.au> added minus sign and close bracket handling in June, 1991. This is revision 1.10, dated 1992/04/03. SEE ALSO
grep(1), regex(3), regexp(3). WILDMAT(3)
All times are GMT -4. The time now is 10:52 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy