Login or Register to Ask a Question and Join Our Community


Shell Programming and Scripting

Target string with gsub

Login to Discuss or Reply to this Discussion in Our Community

 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting Target string with gsub
# 1  
Old 10-12-2013
Target string with gsub
Hey guys,

I am learning awk and came across gsub and testing the target string to do substitution, what am i missing? Thanks in advance.

Code:
echo "this is a summer" | awk '{gsub(/er/, "x", "summer"); print}' 
this is a summer

The following works: but i don't understand the why the above doesn't work!!?

Code:
 echo "this is a summer" | awk '{gsub(/er/, "x", $0); print}'
this is a summx

Last edited by Scrutinizer; 10-12-2013 at 08:38 PM.. Reason: icode to code tags
# 2  
Old 10-12-2013
print is short for print $0, which is the record, the entire line in this case. gsub alters the string specified in the third field. In the first case, $0 does not get altered, in the second case it does....
This User Gave Thanks to Scrutinizer For This Post:
Apollo
# 3  
Old 10-12-2013
gsub 3rd argument should be a variable not a constant like "summer".
# 4  
Old 10-13-2013
Code:
gsub(regexp, replacement [, target])

target is a variable like $0,$1

If you like to just replace in the word summer
Code:
echo "this is a summer" | awk '{gsub(/er/, "x", $4); print}'

or shorter
Code:
echo "this is a summer" | awk '{gsub(/er/, "x", $4)}1'

Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Replace characters in string with awk gsub

Hi I have a source file that looks like a,b,c,d,e,f,g,h,t,DISTI(USD),MSRP(USD),DIST(EUR),MSRP(EUR),EMEA-DISTI(USD),EMEA-MSRP(USD),GLOBAl-DISTI(USD),GLOBAL-MSRP(USD),DISTI(GBP), MSRP(GBP) I want to basically change MSRP(USD) to MSRP,USD and DIST(EUR) to DIST,EUR and likewise for all i'm using... (3 Replies)
Discussion started by: r_t_1601
3 Replies

2. HP-UX

After adding new iscsi target port, still the session state of that target port is showing offline

Hi, I wanted to configure new iscsi port on HPUX system, i added the target port address and configured it, once done, went to array side and searched for that host iqn number , but was nt able to find the same, came to host, then when i ran "iscsiutil -pVS" command it gave me below result ... (0 Replies)
Discussion started by: Vinay Kumar D
0 Replies

3. Shell Programming and Scripting

awk gsub

Hi, I want to print the first column with original value and without any double quotes The output should look like <original column>|<column without quotes> $ cat a.txt "20121023","19301229712","100397" "20121023","19361629712","100778" "20121030A","19361630412","100838"... (3 Replies)
Discussion started by: ysrini
3 Replies

4. Shell Programming and Scripting

GSUB/Regex Help

I am trying to write my gsub regex to replace a bunch of special characters with spaces, so i can split it to an array and look at each word independently. However, my regex skills are slightly lacking and I appear to be missing a quote or something here. I am trying to replace the following... (6 Replies)
Discussion started by: nitrobass24
6 Replies

5. Shell Programming and Scripting

How to use gsub and array

Hello, i'm searching for a solution to this problem. I have 2 files, the first one is like: <HTML> <HEAD> <TITLE>{$String1}</TITLE> </HEAD> <BODY> <P>{$String2}</P> </BODY> </HTML>and the other one: {$String1}; french {$String2}; italian {$String3}; english ... {$StringN}; I... (3 Replies)
Discussion started by: heaven25
3 Replies

6. Shell Programming and Scripting

awk + gsub to search multiple input values & replace with located string + extra text

Hi all. I have the following command that is successfully searching for any one of the strings on all lines of a file and replacing it with the instructed value. cat inputFile | awk '{gsub(/aaa|bbb|ccc|ddd/,"1234")}1' > outputFile This does in fact replace any occurrence of aaa, bbb,... (2 Replies)
Discussion started by: dazhoop
2 Replies

7. Shell Programming and Scripting

target string to delete

Hi all, I have a text file with a lot of records. In each records I have tags like this: =952 \\$aBNCS-CH\\$bBNCS-CH\\$h1989\\$oBNCS-CH0000001\\$pBNCS-CH0000001\\$yJNL =952 \\$aBNCS-C.UNIV\\$bBNCS-C.UNIV\\$h1974-77.\\$oBNCS-C.UNIV0000001\\$pBNCS-C.UNIV0000001\\$yJNL =952... (4 Replies)
Discussion started by: ldiaz2106
4 Replies

8. Shell Programming and Scripting

awk gsub

Hi all I want to do a simple substitution in awk but I am getting unexpected output. My function accepts a time and then prints out a validation message if the time is valid. However some times may include a : and i want to strip this out if it exists before i get to the validation. I have shown... (4 Replies)
Discussion started by: pxy2d1
4 Replies

9. Shell Programming and Scripting

Help with AWK and gsub

Hello, I have a variable that displays the following results from a JVM.... 1602100K->1578435K I would like to collect the value of 1578435 which is the value after a garbage collection. I've tried the following command but it looks like I can't get the > to work. Any suggestions as... (4 Replies)
Discussion started by: npolite
4 Replies

10. Shell Programming and Scripting

Gsub and nawk

Hello I have problem with reg-expr and function gsub(); File that I want to preprocess look like this: int table ; printf(" variable : ", variable) ; Using nawk I try something like this: for ( .... ) { line = $0 reg_expr = "\.\=]*" "" variable "" "\.\=]*" ; gsub( reg_expr... (1 Reply)
Discussion started by: scotty_123
1 Replies
Login or Register to Ask a Question