Visit Our UNIX and Linux User Community


grep with regular expression optional value


 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting grep with regular expression optional value
# 1  
Old 08-06-2009
grep with regular expression optional value

field 12345 12345
field 12345
field 12345 123456

last fleld (from three) is optional, but if it occures It has to be composed only of nummbers and maximum 5 positions long.

If I use:

Code:
grep "^field [0-9]\{5\}"

I get:

field 12345 12345
field 12345
field 12345 123456

But I wont to get just:

field 12345 12345
field 12345

I thought that this will work, but it doesent:
Code:
grep "^field [0-9]\{5\} [0-9]\{0,5\}"

# 2  
Old 08-06-2009
try..
Code:
grep "^field [0-9]\{5\} [0-9]\{0,5\}$" file



---------- Post updated at 10:20 PM ---------- Previous update was at 10:19 PM ----------

remember grep search matching lines. so you should tell it to stop at a certainpoint
Code:
-bash-3.2$ cat file
a
ab
abc
-bash-3.2$ grep ab file
ab
abc
-bash-3.2$ grep ab$ file
ab
-bash-3.2$

# 3  
Old 08-06-2009
Quote:
Originally Posted by ryandegreat25
try..
Code:
grep "^field [0-9]\{5\} [0-9]\{0,5\}$" file

---------- Post updated at 10:20 PM ---------- Previous update was at 10:19 PM ----------

remember grep search matching lines. so you should tell it to stop at a certainpoint
Code:
-bash-3.2$ cat file
a
ab
abc
-bash-3.2$ grep ab file
ab
abc
-bash-3.2$ grep ab$ file
ab
-bash-3.2$

Great, thanks this works. But what if this field is not the last one in the row. Like this:

field 12345 12345 a
field 12345 a
field 12345 123456 a

In that case this ´guy´ dos not work:
Code:
grep "^field [0-9]\{5\} [0-9]\{0,5\} [a-z]$" file

# 4  
Old 08-06-2009
what output you want then?
# 5  
Old 08-06-2009
Quote:
Originally Posted by ryandegreat25
what output you want then?
I wont:

field 12345 12345 a
field 12345 a

But with
Code:
grep "^field [0-9]\{5\} [0-9]\{0,5\} [a-z]$" file

I get:

field 12345 12345 a
# 6  
Old 08-06-2009
this is quite complex.. i couldnt think of anything beside awk.
Code:
awk '{if (length($3) <= 5) {print $0}}' file

# 7  
Old 08-06-2009
Quote:
Originally Posted by necroman08
...
But what if this field is not the last one in the row. Like this:

field 12345 12345 a
field 12345 a
field 12345 123456 a
...
I guess in this case, your conditions are:

(i) Print the line if the number of fields is less than 3
(ii) If the 3rd field exists, print the line if it does not consist of any digits. Its length does not matter here.
(iii) If the 3rd field exists, print the line if it consists ONLY of digits and has a length of 5 or less.
(iv) There can be more than 3 fields, and the line will be printed as long as rules (ii) and (iii) are satisfied.

So for the data below, you want to display lines 1,2,4 and 7:

Code:
$
$ cat -n data.txt
     1  field 12345 12345 a
     2  field 12345 a
     3  field 12345 123456 a
     4  field 12345
     5  field 12345 12aQ~
     6  field 12345 12aQ~ 123
     7  field 12345 1340 4578 abc AB#xy2
$
$

Perl script:

Code:
$
$ perl -ne '@a=split; $f=$a[2]; ($x=$f)=~s/\d//g; ($y=$f)=~s/\D//g;
>           print if ( $#a<2 or
>                      ($#a>=2 and $x eq $f) or
>                      ($#a>=2 and $y eq $f and length($f)<=5)
>                    )' data.txt
field 12345 12345 a
field 12345 a
field 12345
field 12345 1340 4578 abc AB#xy2
$
$

tyler_durden

Previous Thread | Next Thread
Test Your Knowledge in Computers #206
Difficulty: Easy
Exterior Gateway Protocol (EGP) is a modern, widely used, routing protocol.
True or False?

10 More Discussions You Might Find Interesting

1. UNIX for Beginners Questions & Answers

Grep regular expression

I want to track only below: I am using below, but it doesn't work: (6 Replies)
Discussion started by: proactiveaditya
6 Replies

2. Shell Programming and Scripting

Grep + Regular expression or

Hi , I have few lines like A20120101.ANU.ZIP A20120401.ABC.ZIP A20120105.KJK.ZIP A20120809.JUG.ZIP A20120101.MAT.ZIP B20120301.ANU.XIP I want to filter by 1. Files starting with A and Ending With Z ( ^A.*.ZIP$) 2. And either ANU, or KJK or MAT in the file name. Hope my... (6 Replies)
Discussion started by: Anupam_Halder
6 Replies

3. UNIX for Dummies Questions & Answers

grep with variable and regular expression

i have a command line like this in csh script grep -i "$argv$" which i wanted to select the line ending with string provided as argument but it couldn't interpret the '$' (ending with).. any help? (3 Replies)
Discussion started by: ymc1g11
3 Replies

4. 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

5. Shell Programming and Scripting

Help with grep / regular expression

Hi, Input file: -13- -1er- -1xyz1- -1xz12- -2ab1- -2ab2-- -143- Code: grep '^*\-' input.txt Wrong output: -13- -1xyz1- -2ab1- -2ab2-- (4 Replies)
Discussion started by: dragon.1431
4 Replies

6. Shell Programming and Scripting

grep and regular expression

Hi, I am executing a svnlook command to check to see if the following line exists. I need a regular expression to represent the line. A /test/test1/qa/test2/index.html A /test/test1/qa/test3/test.jpg A /test/test1/qa/test3/test1.jpg A /test/test1/qa/test4/test.swf I just need to extract... (9 Replies)
Discussion started by: kminkeller
9 Replies

7. Shell Programming and Scripting

grep regular expression

please can someone tell me what the following regrex means grep "^aa*$" <file> I thought this would match any word beginning with aa and ending with $, but it doesnt. Thanks in advance Calypso (7 Replies)
Discussion started by: Calypso
7 Replies

8. Shell Programming and Scripting

grep with regular expression

Hi, guys. I have one question, hope somebody can give me a hand I have a file called passwd, the contents of it arebelow: *********************** ... goldsimj:x:5008:200: goldsij2:x:5009:200: whitej:x:5010:201: brownj:x:5011:202: goldsij3:x:5012:204: greyp:x:5013:203: ...... (6 Replies)
Discussion started by: daikeyang
6 Replies

9. UNIX for Advanced & Expert Users

regarding grep regular expression

When i do ls -ld RT_BP* i am getting the following list. drwxrwx--- 2 user group 256 Oct 17 10:09 RT_BP809 drwxrwx--- 2user group 256 Oct 17 10:09 RT_BP809.O drwxrwx--- 2 user group 256 Oct 17 10:09 RT_BP810 drwxrwx--- 2user group 256 Oct... (2 Replies)
Discussion started by: ukatru
2 Replies

10. Shell Programming and Scripting

grep : regular expression

guys, my requirment goes like this: I have a file, and wish to filter out records where 1. The first letter is o or O and 2. The next 4 following letter should not be ther I do not wish to use pipe and wish to do it in one shot. The best expression I came up with is: grep ^*... (10 Replies)
Discussion started by: RishiPahuja
10 Replies

Featured Tech Videos