CODEWITHSUNDEEP
bashsed
user3158281
user3158281

Reputation: 41

Sed to replace specific string, in multiple lines which are between some pattern

I have a simple question (I think), I need to replace a specific string which occurs in multiple lines in a file (verilog). These lines are themselves between specific patterns

ex: 

lk
lk
lk
lk
lk

//comment1
input [5:0]a,
input [3:0]b,
input c,
input [4:0]d,
input f,

//comment2
lm
lm
lm
lm

I need to replace "input" with "logic" between "comment1" and "comment2" keeping them as it is in the final result (quotes not included, only for understanding)

Right now what I have is

sed '/\/comment1/,/\/comment2/s/input/logic/g' file1.sv > file2.sv

the result I get is 

lk
lk
lk
lk
lk

//comment1
logic
logic
logic
logic
logic

//comment2
lm
lm
lm
lm

The rest of the text after logic is gone, I need to preserve that

Can someone please help, I will be grateful...

Upvotes: 3

Views: 1844

Answers (2)

jackbenny
jackbenny

Reputation: 13

I have just tested your sed command, and to me it worked out just perfect. The only thing I can see that is wrong is that you have forgotten the last slash in front of the comment-lines. It worked for me either way, but the correct line would be

sed '/\/\/comment1/,/\/\/comment2/s/input/logic/g' file1.sv > file2.sv

As you can see I have one more "/" in each of the comment-lines. Try it out and see if it helps. I am running GNU sed version 4.2.1 here.

To answer your question in the comment about reading the filename from the command line inside a script this would be the most simple way

#!/bin/bash
sed '/\/\/comment1/,/\/\/comment2/s/input/logic/g' "$1" > file2.sv
exit 0

$1 means the first argument. If would like to be able to specifiy the output file as well you do as this

#!/bin/bash
sed '/\/\/comment1/,/\/\/comment2/s/input/logic/g' "$1" > "$2"
exit 0

Whereas this means the first argument is the input file, the second argument is the output file. The quotation might not be necessary, but it's a good idea to quote strings (and the filenames are strings basically).

Upvotes: 0

anubhava
anubhava

Reputation: 784898

You can use this sed command:

sed -i.bak '/\/\/comment1/,/\/\/comment2/s/\<input\>/logic/g' file
  • /\/\/comment1/,/\/\/comment2/ is to search text between 2 comment blocks
  • \<input\> is for matching input with word boundaries
  • s/\<input\>/logic/g is for replacing "input" with "logic"

Upvotes: 1

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