Visit The New, Modern Unix Linux Community

Awk: split and gensub query

Thread Tools Search this Thread
Top Forums UNIX for Beginners Questions & Answers Awk: split and gensub query
# 1  
Awk: split and gensub query

Hi All,

Thanks for answering my previous question. Could you please explain the highlighted code?

awk -v pos='9 27 39 54 59 64 71 78 83 103 108' 'BEGIN{split(pos,var)} {for (i in var) $0=gensub(/./,"|",var[i])} 1' test.txt | head

I understood that the split function splits the pos string into an array but I am confused on the usage of gensub function, especially var[i]. It wold be helpful if there is any tool which I use to visualize the steps.


Last edited by mrcool4; 08-13-2019 at 05:09 AM.. Reason: Added more info
# 2  
You are right - the pos variable is split into the var array. Then, in all input lines ($0), gensub (a specific gawk function) replaces the characters (no matter what they are!) at the positions in var by the pipe symbol, as said in man gawk:

gensub(regexp, replacement, how [, target])
Search the target string target for matches of the regular expression regexp. If how is a string beginning with ‘g' or ‘G' (short for “global”¯), then replace all matches of regexp with replacement. Otherwise, treat how as a number indicating which match of regexp to replace. Treat numeric values less than one as if they were one. If no target is supplied, use $0. Return the modified string as the result of the function. The original target string is not changed.
This User Gave Thanks to RudiC For This Post:
# 3  
Thanks Rudic. Got it. I have been trying to understand by simplifying the function and finally understood by trying with a few examples.

Previous Thread | Next Thread
Thread Tools Search this Thread
Search this Thread:
Advanced Search

Test Your Knowledge in Computers #995
Difficulty: Medium
IBM announced its System/370 series in 1970 with full virtualization features.
True or False?

10 More Discussions You Might Find Interesting

1. Programming

Need sql query to string split and normalize data

Hello gurus, I have data in one of the oracle tables as as below: Column 1 Column 2 1 NY,NJ,CA 2 US,UK, 3 AS,EU,NA fyi, Column 2 above has data delimited with a comma as shown. I need a sql query the produce the below output in two columns... (5 Replies)
Discussion started by: calredd
5 Replies

2. Shell Programming and Scripting

awk split and awk calculation in the same command

I am trying to run the awk below. My question is when I split the input, then run anotherawk to perform a calculation using that splitas the input there are no issues. When I try to combine them the output is not correct, is the split not working or did I do it wrong? Thank you :). input ... (8 Replies)
Discussion started by: cmccabe
8 Replies

3. Shell Programming and Scripting

Gawk gensub, match capital words and lowercase words

Hi I have strings like these : Vengeance mitt Men Vengeance gloves Women Quatro Windstopper Etip gloves Quatro Windstopper Etip gloves Girls Thermobite hooded jacket Thermobite Triclimate snow jacket Boys Thermobite Triclimate snow jacket and I would like to get the lower case words at... (2 Replies)
Discussion started by: louisJ
2 Replies

4. Shell Programming and Scripting

awk query

Hi, I have a sample file in the following format. 000013560240|000013560240|001|P|155|99396|0||SS00325665| 000013560240|000013560240|002|P|17|99000|0||SS00325665| 000013560240|000013560240|002|F|-17|99000|0|R|SS00325665| 000013560240|000013560240|003|P|20|82270|0||SS00325665|... (3 Replies)
Discussion started by: nua7
3 Replies

5. Shell Programming and Scripting

awk to split one field and print the last two fields within the split part.

Hello; I have a file consists of 4 columns separated by tab. The problem is the third fields. Some of the them are very long but can be split by the vertical bar "|". Also some of them do not contain the string "UniProt", but I could ignore it at this moment, and sort the file afterwards. Here is... (5 Replies)
Discussion started by: yifangt
5 Replies

6. UNIX for Dummies Questions & Answers

gensub and arraywith awk

Hi ! I would need some help for something I don't understand :confused: input: 111|2 Y Z blue. 333|4 W X blue.; 5 Y Z red. 666|7 W X red.; 8 Y Z blue. 999|10 U V red.; 11 W X blue.; 12 Y Z red. From $2, I would like to remove the sub-strings containing "blue" (and the... (4 Replies)
Discussion started by: beca123456
4 Replies

7. Shell Programming and Scripting

gawk and gensub

Hi, $ echo "Hellooo" | gawk '{print gensub(/o{3}/, "z", 1)}' doesn't return "Hellz" as expected while: $ echo "Hellooo" | awk '{print gensub(/o+/, "z", 1)}' produces "Hellz" correctly. Are the {m,n} quantifiers not supported in gensub? I know that sub or gsub could do the job. It's just an... (2 Replies)
Discussion started by: ripat
2 Replies

8. UNIX for Dummies Questions & Answers

some query in awk

Hi , I want to assign a value to variable which will have size of the file that is we have following files for eg: ls -ltr -rw-rw-r-- 1 dsadmin dstage 34 Oct 29 12:14 some.txt -rw-rw-r-- 1 dsadmin dstage 0 Oct 29 14:52 eg.txt -rwxrwxr-x 1 dsadmin dstage 1453 Oct... (2 Replies)
Discussion started by: Amey Joshi
2 Replies

9. UNIX for Dummies Questions & Answers

Split a file with no pattern -- Split, Csplit, Awk

I have gone through all the threads in the forum and tested out different things. I am trying to split a 3GB file into multiple files. Some files are even larger than this. For example: split -l 3000000 filename.txt This is very slow and it splits the file with 3 million records in each... (10 Replies)
Discussion started by: madhunk
10 Replies

10. UNIX for Dummies Questions & Answers

Query In awk

Is it possible to have a pattern as RS in awk. For Example pl. go through the statement; " Account Serial Number: 88888888 TT00X000000XXXXXXXXXXXXX SS00X000000XX.000,XXXXXXXXXXXXXXXXXX0000XXXXXXX0000000000 WW00X0000000XX000000000000MMMMMMM MMMMMMM0000AA11110000000000000000000000000... (1 Reply)
Discussion started by: raguramtgr
1 Replies

Featured Tech Videos