Visit Our UNIX and Linux User Community


Update a field using awk and keep the formatting.


 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting Update a field using awk and keep the formatting.
# 1  
Old 07-25-2014
Update a field using awk and keep the formatting.

Look at this simple example.
Code:
echo "  2 4 6" | awk '{$2+=3;$3-=1}1'
2 7 5

Is there a simple way to update a field and at the same time keep the formatting?

I would like to get it like this
Code:
  2 7 5

I have tested both sub and gsub, it reformat too.
# 2  
Old 07-25-2014
Anytime you reset a numbered field (such as $2=x or sub(regex, replacement, $n)) for n not equal to 0), $0 is recalculated. For the general case, you could try something like:
Code:
(	printf "  2 4 6\n"
	printf "1\t3\t7\t\n"
	printf "\t xyz\t 2\t 3 with more fields\n"
) | awk '
{	n = split($0, delims, /[^[:space:]]*/)
	$2+=3
	$3-=1
	for(i = 1; i <= n; i++)
		printf("%s%s", delims[i], $i)
	print ""
}'

which produces the output:
Code:
  2 7 5
1	6	6	
	 xyz	 5	 2 with more fields

If you want to try this on a Solaris/SunOS system, change awk to /usr/xpg4/bin/awk, /usr/xpg6/bin/awk, or nawk.

The loop printing the modified lines and the following print command can be simplified to a single printf command if you know that there are always three fields.

Last edited by Don Cragun; 07-25-2014 at 06:48 AM.. Reason: Add note explaining why problem occurs...
This User Gave Thanks to Don Cragun For This Post:
# 3  
Old 07-25-2014
Not a quick and short solution, but it works Smilie
I see that you store the number of spaces in an array, and then add i back.

Previous Thread | Next Thread
Test Your Knowledge in Computers #213
Difficulty: Medium
OSPF-TE is an extension to OSPF extending the expressivity to allow for traffic engineering and use on non-IP networks.
True or False?

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

awk to assign points to variables based on conditions and update specific field

I have been reading old posts and trying to come up with a solution for the below: Use a tab-delimited input file to assign point to variables that are used to update a specific field, Rank. I really couldn't find too much in the way of assigning points to variable, but made an attempt at an awk... (4 Replies)
Discussion started by: cmccabe
4 Replies

2. Shell Programming and Scripting

awk to update field using matching value in file1 and substring in field in file2

In the awk below I am trying to set/update the value of $14 in file2 in bold, using the matching NM_ in $12 or $9 in file2 with the NM_ in $2 of file1. The lengths of $9 and $12 can be variable but what is consistent is the start pattern will always be NM_ and the end pattern is always ;... (2 Replies)
Discussion started by: cmccabe
2 Replies

3. Shell Programming and Scripting

awk to update value in field of out file using contents of another Ask

In the out.txt below I am trying to use awk to update the contents of $9.. If $9 contains a + or - then $8 of out.txt is used as a key to lookup in $2 of file. When a match ( there will always be one) is found the $3 value of that file is used to update $9 of out.txt separated by a :. So the... (6 Replies)
Discussion started by: cmccabe
6 Replies

4. Shell Programming and Scripting

awk to update field in file2 if not the same as file1

Trying to use awk to: update $2 in file2 with the $2 value in file1, if $1 in file1 matches $13 in file2, which is tab-delimeted. The $2values may already be the same so in that case nothing happens and the next line is processed. There are exactly 4,605 unique $13 values. Thank you :). ... (4 Replies)
Discussion started by: cmccabe
4 Replies

5. Shell Programming and Scripting

awk to update value in field based on another field

In the tab-delimeted input file below I am trying to use awk to update the value in $2 if TYPE=ins in bold, by adding the value of HRUN= in italics. In the below since in line 1 TYPE=ins the 117282541 value in $2 has 6 added because that is the value of HRUN=. Hopefully the awk is a start but I... (2 Replies)
Discussion started by: cmccabe
2 Replies

6. Shell Programming and Scripting

awk to update field in file based of match in another

I am trying to use awk to match two files that are tab-delimited. When a match is found between file1 $1 and file2 $4, $4 in file2 is updated using the $2 value in file1. If no match is found then the next line is processed. Thank you :). file1 uc001bwr.3 ADC uc001bws.3 ADC... (4 Replies)
Discussion started by: cmccabe
4 Replies

7. Shell Programming and Scripting

awk to update field file based on match

If $1 in file1 matches $2 in file2. Then the value in $2 of file2 is updated to $1"."$2 of file2. The awk seems to only match the two files but not update. Thank you :). awk awk 'NR==FNR{A ; next} $1 in A { $2 = a }1' file1 file2 file1 name version NM_000593 5 NM_001257406... (3 Replies)
Discussion started by: cmccabe
3 Replies

8. Shell Programming and Scripting

How to check field formatting of input file?

Hi, I had input file with below data, abcdefghij;20100903040607;1234567891;GLOBAL; Having values of fields with seperated by semi-colon (;) and ended with line feed (\n). Through shell script, how can I check the field formatting? Thanks in advance. (18 Replies)
Discussion started by: Poonamol
18 Replies

9. UNIX for Dummies Questions & Answers

Conversion problem with date field and formatting.

Hi, My input file contains the record(s) as below with space as FS. 01-01024180 35000 MV010 02/03/09 0306 03060226 03 02-00410330 470000 MV010 02/03/09 0301 03010276 03 1. I need to convert the field 02/03/09 (dd/mm/yy) to yyyymmdd yet retain the Field separator. Using the modified... (2 Replies)
Discussion started by: talk2pawee
2 Replies

10. Shell Programming and Scripting

CSV formatting with prefixing, appending and padding field

Hi I have a very large csv file with some hundreds of thousands of rows of data. The data is in the following format: Up to four alpha numeric characters for the first word. This is either set as 2 characters followed by 2 spaces, or as a single 4character word. This is then followed by an 8... (7 Replies)
Discussion started by: meself
7 Replies

Featured Tech Videos