CODEWITHSUNDEEP
bashsedreplace
Roloka
Roloka

Reputation: 191

Replace the second entry in all lines containing a specific string in bash

I would like to replace the second entry of all (space or tab-separated) lines containing a specific string. In the following text

1078.732700000 0.00001000 1 0 0 39 13 27 0 0 0 40 14 26 81SaWoLa.43 BAD LABEL, REASSIGNED 

-1077.336700000 0.00001000 1 0 0 45 12 34 0 0 0 46 13 34 81SaWoLa.48 BAD LABEL

I would like to replace 0.00001000 by 0.00005214 (searching for the string 81SaWoLa). The result should be

1078.732700000 0.00005214 1 0 0 39 13 27 0 0 0 40 14 26 81SaWoLa.43 BAD LABEL, REASSIGNED 

-1077.336700000 0.00005214 1 0 0 45 12 34 0 0 0 46 13 34 81SaWoLa.48 BAD LABEL

Could you please help me how to perform it?

Upvotes: 1

Views: 98

Answers (3)

Andreas Louv
Andreas Louv

Reputation: 47119

Use awk:

$ awk '/pattern/ { $2 = "new string." }; 1' input.txt

In your case:

$ awk '/81SaWoLa/ { $2 = "0.00005214" }; 1' input.txt
#      ^^^^^^^^^^   ^^^^^^^^^^^^^^^^^    ^
#      For lines    Replace second       Print each line, same as:
#      matching     column with          ``{ print $0 }''. ``$0''
#      81SaWoLa     ``0.00005214''       contains the whole line.

Use -v name=val to specify a variable:

$ awk -v pat="81SaWoLa"   \
      -v rep="0.00005214" \
      '$0 ~ pat { $2 = rep }; 1' input.txt

Upvotes: 1

CWLiu
CWLiu

Reputation: 4043

You may use awk to achieve your goal more easily.

$ awk '/81SaWoLa/{$2="0.00005214"}1' file
1078.732700000 0.00005214 1 0 0 39 13 27 0 0 0 40 14 26 81SaWoLa.43 BAD LABEL, REASSIGNED

-1077.336700000 0.00005214 1 0 0 45 12 34 0 0 0 46 13 34 81SaWoLa.48 BAD LABEL

With the variables to be used, used the command as followed,

$ var1=81SaWoLa
$ var2=0.00005214
$ awk -v var1=$var1 -v var2=$var2 '$0 ~ var1{$2=var2}1' file
1078.732700000 0.00005214 1 0 0 39 13 27 0 0 0 40 14 26 81SaWoLa.43 BAD LABEL, REASSIGNED

-1077.336700000 0.00005214 1 0 0 45 12 34 0 0 0 46 13 34 81SaWoLa.48 BAD LABEL

Upvotes: 2

Weike
Weike

Reputation: 1270

Try this for GNU sed:

$ cat input.txt 
1078.732700000 0.00001000 1 0 0 39 13 27 0 0 0 40 14 26 81SaWoLa.43 BAD LABEL, REASSIGNED 

-1077.336700000 0.00001000 1 0 0 45 12 34 0 0 0 46 13 34 81SaWoLa.48 BAD LABEL
$ sed -r '/81SaWoLa/s/^([^ \t]+[ \t]+)[^ \t]+(.*)/\10.00005214\2/' input.txt 
1078.732700000 0.00005214 1 0 0 39 13 27 0 0 0 40 14 26 81SaWoLa.43 BAD LABEL, REASSIGNED 

-1077.336700000 0.00005214 1 0 0 45 12 34 0 0 0 46 13 34 81SaWoLa.48 BAD LABEL

Upvotes: 2

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