Login or Register to Ask a Question and Join Our Community


UNIX for Dummies Questions & Answers

Is this regex efficient?

 
Thread Tools Search this Thread
Top Forums UNIX for Dummies Questions & Answers Is this regex efficient?
# 1  
Old 02-09-2011
Is this regex efficient?
I want to match the red portion:
9784323456787-Unknown Phrase with punctuation "Some other PhrASE."

Is this the best regex to match this?
'978[0-9]\{10\}-[^"]*'
# 2  
Old 02-09-2011
you can test it like this:

Code:
echo "9784323456787-Unknown Phrase with punctuation \"Some other PhrASE.\"" |sed 's/\(978[0-9]\{10\}-[^"]*\).*/\1/'
9784323456787-Unknown Phrase with punctuation

# 3  
Old 02-09-2011
Thanks Yinuemi, I know that technique in sed, and I know my regex matches, I just want to know if there could be any failing case (besides if there were double quotes in the expression, which I know will not happen".. I also wanted to know if there was any shorter, mnore efficient regex than the one I used.. Preferably only posix or extended regex, no funky perl please.
# 4  
Old 02-10-2011
try:
Code:
'[0-9].*-[^"]*'

# 5  
Old 02-10-2011
Code:
$ echo '9784323456787-Unknown Phrase with punctuation "Some other PhrASE."' | ruby -e 'puts gets.split(/"/)[0]' 
9784323456787-Unknown Phrase with punctuation

 
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Sendmail K command regex: adding exclusion/negative lookahead to regex -a@MATCH

I'm trying to get some exclusions into our sendmail regular expression for the K command. The following configuration & regex works: LOCAL_CONFIG # Kcheckaddress regex -a@MATCH +<@+?\.++?\.(us|info|to|br|bid|cn|ru) LOCAL_RULESETS SLocal_check_mail # check address against various regex... (0 Replies)
Discussion started by: RobbieTheK
0 Replies

2. Shell Programming and Scripting

Perl, RegEx - Help me to understand the regex!

I am not a big expert in regex and have just little understanding of that language. Could you help me to understand the regular Perl expression: ^(?!if\b|else\b|while\b|)(?:+?\s+){1,6}(+\s*)\(*\) *?(?:^*;?+){0,10}\{ ------ This is regex to select functions from a C/C++ source and defined in... (2 Replies)
Discussion started by: alex_5161
2 Replies

3. UNIX for Advanced & Expert Users

Efficient way to grep

Hi Experts, I've been trying simple grep to search for a string in a huge number of files in a directory. grep <pattern> * this gives the search results as well as the following - grep: <filename>: Permission denied grep: <filename>: Permission denied for files which I don't have... (4 Replies)
Discussion started by: sumoka
4 Replies

4. Shell Programming and Scripting

Converting perl regex to sed regex

I am having trouble parsing rpm filenames in a shell script.. I found a snippet of perl code that will perform the task but I really don't have time to rewrite the entire script in perl. I cannot for the life of me convert this code into something sed-friendly: if ($rpm =~ /(*)-(*)-(*)\.(.*)/)... (1 Reply)
Discussion started by: suntzu
1 Replies

5. UNIX for Advanced & Expert Users

efficient repace

some of the data i receive has been typed in manually due to which there are often places where i find 8 instead of ( and the incorrect use of case what according to you is the best way to correct such data. The data has around 20,000 records. The value i want to change is in the 4th field.... (2 Replies)
Discussion started by: VGR
2 Replies

6. Shell Programming and Scripting

efficient search

Hi, i have 2 files each with 200K lines. Each line contains a number. Now, i need to get the list of numbers existing in one fine and NOT in other file. I'm doing this by reading each number from 1 file and grepping on other file. But this taking LOT of time. Is there any efficient way of doing... (14 Replies)
Discussion started by: prvnrk
14 Replies

7. Shell Programming and Scripting

help on most efficient search

Hello, We have a directory with 15 sub-directories where each sub-directory contains 1.5 to 2 lakhs of files in it. Daily, around 300-500 files will be uploaded to each sub-directory. Now, i need to get the list of files received today in most efficient way. I tried using "find with newer... (16 Replies)
Discussion started by: prvnrk
16 Replies

8. Shell Programming and Scripting

Can you suggest a more efficient way for this?

Hi I have the following at the end of a service shutdown script used in part of an active-passive failover setup: ### # Shutdown all primary Network Interfaces # associated with failover ### # get interface names based on IP's # and shut them down to simulate loss of # heartbeatd ... (1 Reply)
Discussion started by: mikie
1 Replies

9. Shell Programming and Scripting

Efficient way of Awk

Hi, Can someone let me know if the below AWK can be made much simpler / efficient ? I have 200 fields, I need to substr only the last fields. So i'm printing awk -F~ 'print {$1, $2, $3....................................$196,$197 , susbstr($198,1,3999), substr($199,1,3999)..}' Is there a... (4 Replies)
Discussion started by: braindrain
4 Replies

10. Shell Programming and Scripting

Is there a more efficient way?

I'm using korn shell to connect to oracle, retrieve certain values, put them in a list, and iterate through them. While this method works, I can't help but think there is an easier method. If you know of one, please suggest a shorter, more efficient method. ############### FUNCTIONS ... (6 Replies)
Discussion started by: SelectSplat
6 Replies
Login or Register to Ask a Question