Login or Register to Ask a Question and Join Our Community


Shell Programming and Scripting

expr command to extract words

Login to Discuss or Reply to this Discussion in Our Community

 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting expr command to extract words
# 1  
Old 09-05-2010
expr command to extract words
how to use expr command to retrieve all the words before the equal sign "=" with shell script
# 2  
Old 09-05-2010
expr is not used for that. see the man page for detaild. awk may work for this task.
# 3  
Old 09-05-2010
bash substitution
Code:
~$ A="fJH DFKGF= ,jfhF"
~$ echo  ${A%=*}
fJH DFKG

# 4  
Old 09-05-2010
Here is an example of how to do what you want to do:
Code:
$ A="foo=bar"
$ echo $A
foo=bar
$ expr "$A" : '\(.*\)=.*'
foo

From IEEE Std 1003.1:2008
Quote:
The ':' matching operator shall compare the string resulting from the evaluation of expr1 with the regular expression pattern resulting from the evaluation of expr2. Regular expression syntax shall be that defined in the Base Definitions volume of IEEE Std 1003.1-2001, Section 9.3, Basic Regular Expressions, except that all patterns are anchored to the beginning of the string (that is, only sequences starting at the first character of a string are matched by the regular expression) and, therefore, it is unspecified whether '^' is a special character in that context. Usually, the matching operator shall return a string representing the number of characters matched ( '0' on failure). Alternatively, if the pattern contains at least one regular expression subexpression "[\(...\)]", the string corresponding to "\1" shall be returned.
This User Gave Thanks to fpmurphy For This Post:
frank_rizzo
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. UNIX for Beginners Questions & Answers

Extract Bracketed Words

Hi there, Unixers I need to extract ALL the words from a text which aresurrounded by square brackets. I am using this piece of code sed 's/.*\.*/\1/g' inputfile > outputfile but I only get one word for every paragraph, why? Please use CODE tags as required by forum rules! (7 Replies)
Discussion started by: eldeingles
7 Replies

2. Shell Programming and Scripting

Extract words before and after a certain word.

I have a sample text file with file name: sample.txt The text file has the following text. this is an example text where we have to extract certain words before and after certain word these words can be used later to get more information I want to extract n (a constant) words before and... (2 Replies)
Discussion started by: shoaibjameel123
2 Replies

3. Shell Programming and Scripting

Extract words from a pipe

Hello, Currently, I have this output from my application : ------------------------------------------------- Log viewer/Tmp1 (Jun 29 2011 09:48) ------------------------------------------------- BlalbalbaBlalbalba..Blalbalba..Blalbalba..Blalbalba..Blalbalba..Blalbalba..Blalbalba....... (3 Replies)
Discussion started by: acidoangel
3 Replies

4. Shell Programming and Scripting

expr command help

I'm trying to check if a variable'd string is only one character and use that in an if statement the only way I could find is: $expr "${var}" : . # expr STRING : regrep where the "." is the grep wildcard for any single character. Whats wrong with my code here and is there a... (3 Replies)
Discussion started by: Tewg
3 Replies

5. UNIX for Dummies Questions & Answers

Extract words to new file

Hi there, Unix Gurus Working with big listings of english sentences for my pupils, of the type: 1. If the boss's son had been , someone would have asked for money by now. 2. Look, I haven't a crime, so why can't you let me go? .... I wondered how to extract the words between brackets in... (7 Replies)
Discussion started by: eldeingles
7 Replies

6. Shell Programming and Scripting

Usage of grep command to extract only the words.

Dear Folks, I am a newbee to UNIX. I want to extract the SQLSTATE from a log file. For example the log file content is SQL0010N The string constant beginning with "' from table1 a, table 2" does not have an ending string delimiter. SQLSTATE=42603 when I give the the command as ... (4 Replies)
Discussion started by: dinesh1985
4 Replies

7. Shell Programming and Scripting

expr command

Hi Can anyone explain me the usage of this command and the arguments used here and what will be the expected output : v_num=`expr nav_d_20100204_1759 : '*\(*\)'` what will be the value returned in v_num. Thanks in Advance!!! Regards Naveen Purbia (3 Replies)
Discussion started by: trying_myluck
3 Replies

8. UNIX for Dummies Questions & Answers

using the expr command

Hi friends how can i execute expr $va1 * $var2 provided i m not supposed to use '/' also the nglob variable is turned off. (4 Replies)
Discussion started by: ashishj
4 Replies

9. UNIX for Advanced & Expert Users

How to extract two words at the same time.

Hi, Can anyone please let me know, how to extract two lines at the same time. In specific,I have a file containing list of devices, such as router1 and switch2 below. I want to get all the lines which has "#" and all the lines which has "down" router1#sh ip int br Interface ... (6 Replies)
Discussion started by: Aejaz
6 Replies

10. UNIX for Dummies Questions & Answers

expr command

I am looking for the correct syntax on the expr command in UNIX. I have a script that I am building at the moment. the script is creating file1 that is an actual .sql file that is going inside the oracle database to get some information in there. It take that information, puts it inside another... (2 Replies)
Discussion started by: wolf
2 Replies
Login or Register to Ask a Question