What's the difference between \d , [:digit:], and [0-9] in regular expression ?

Thread Tools Search this Thread
Top Forums Shell Programming and Scripting What's the difference between \d , [:digit:], and [0-9] in regular expression ?
# 8  
Old 09-01-2011
On fedora 15 :
[river@localhost Desktop]$ [[ "123" =~ \\b[0-9]{3}\\b ]] && echo "ok" || echo "error"
[river@localhost Desktop]$  [[ "123" =~ "\b[0-9]{3}\b" ]] && echo "ok" || echo "error"

# 9  
Old 09-01-2011
Word boundaries could be marked also by \< and \>,
did you try that syntax?

4.1.10(4)-release$ reg='\<[0-9]{3}\>'
4.1.10(4)-release$ [[ "123" =~ $reg ]] && echo "ok" || echo "error"

Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Regular expression

Hello Gurus, I am looking for regular expressions for awk to filter on second column 2nd and 3rd digit Using in code something like: awk '{if ( $2 == "0::" ) print} source file: 0 0:0:0 FC 15 normal 559104 51200 0:3:1* 1:3:1 600 1 0:0:1 FC 15 normal ... (2 Replies)
Discussion started by: vishalgoyal
2 Replies

2. Shell Programming and Scripting

Regular expression for 6 digit number present in a line

Hello Team, i have a file test1.txt, in which i have to grep only the 6 digit number from it, Could you pls help in this. $cat test1.txt <description>R_XYZ_1.6 r370956</description> $ grep "\{6\}" test1.txt <description>R_XYZ_1.6 r370956</description> i need output as 370956. ... (3 Replies)
Discussion started by: chandana hs
3 Replies

3. UNIX for Dummies Questions & Answers

Difference between space and [[:space:]] in regular expression

May I know the difference between space in keyboard and ] in regular expression I entered the following find . -type f -print | xargs grep -n 'dt=' | cut -d":" -f3 | sed 's/^ *dt=/dt=/g' After "^" there is a space. and the result is... dt=`date +%Y%m%d%H%M%S` dt=`date +%Y%m%d`... (6 Replies)
Discussion started by: bobbygsk
6 Replies

4. UNIX for Advanced & Expert Users

sed: -e expression #1, char 0: no previous regular expression

Hello All, I'm trying to extract the lines between two consecutive elements of an array from a file. My array looks like: problem_arr=(PRS111 PRS213 PRS234) j=0 while } ] do k=`expr $j + 1` sed -n "/${problem_arr}/,/${problem_arr}/p" problemid.txt ---some operation goes... (11 Replies)
Discussion started by: InduInduIndu
11 Replies

5. Programming

Perl: How to read from a file, do regular expression and then replace the found regular expression

Hi all, How am I read a file, find the match regular expression and overwrite to the same files. open DESTINATION_FILE, "<tmptravl.dat" or die "tmptravl.dat"; open NEW_DESTINATION_FILE, ">new_tmptravl.dat" or die "new_tmptravl.dat"; while (<DESTINATION_FILE>) { # print... (1 Reply)
Discussion started by: jessy83
1 Replies

6. Shell Programming and Scripting

Integer expression expected: with regular expression

CA_RELEASE has a value of 6. I need to check if that this is a numeric value. if not error. source $CA_VERSION_DATA if * ] then echo "CA_RELESE $CA_RELEASE is invalid" exit -1 fi + source /etc/ncgl/ca_version_data ++ CA_PRODUCT_ID=samxts ++ CA_RELEASE=6 ++ CA_WEEK_NO=7 ++... (3 Replies)
Discussion started by: ketkee1985
3 Replies

7. Shell Programming and Scripting

Regular expression

Hi I have to extract the first field and the last %field of the following out put.. /home (/abc/def/bhd ) : 522328 total allocated Kb 319448 free allocated Kb ... (2 Replies)
Discussion started by: Harikrishna
2 Replies

8. Linux

Regular expression to extract "y" from "abc/x.y.z" .... i need regular expression

Regular expression to extract "y" from "abc/x.y.z" (2 Replies)
Discussion started by: rag84dec
2 Replies

9. Shell Programming and Scripting

regular expression

Hi all, My log file is like 19:40:22 INFO :Total time taken to Service External Request---15ms 19:40:22 INFO : External service failed with status KO 19:40:22 FATAL: External service failed with status KO 19:40:22 DEBUG : Batch started with 19:40:22 ERROR: Member: dmidecode.x86_64... (1 Reply)
Discussion started by: subin_bala
1 Replies

10. Shell Programming and Scripting

Regular Expression + Aritmetical Expression

Is it possible to combine a regular expression with a aritmetical expression? For example, taking a 8-numbers caracter sequece and casting each output of a grep, comparing to a constant. THX! (2 Replies)
Discussion started by: Z0mby
2 Replies
Login or Register to Ask a Question