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Insert new pattern in newline after the nth occurrence of a line pattern - Bash in Ubuntu 12.04

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Top Forums Shell Programming and Scripting Insert new pattern in newline after the nth occurrence of a line pattern - Bash in Ubuntu 12.04
# 1  
Old 09-13-2012
Insert new pattern in newline after the nth occurrence of a line pattern - Bash in Ubuntu 12.04
Hi,

I am getting crazy after days on looking at it:
Bash in Ubuntu 12.04.1

I want to do this:
pattern="system /path1/file1 file1"
new_pattern=" data /path2/file2 file2"
file to edit: data.db

- I need to search in the file data.db for the nth occurrence of pattern
- pattern must match a complete line
- insert after pattern a new line with new_pattern

Sed in my installed Ubuntu does not seem to accept /c or /a commands, only -i !!

So, I tried this:
Code:
sed "s%system /path1/file1 file1%&\n    data /path2/file2 file2%" -i data.db

Which works except:
1- all occurrences of pattern will be replaced in data.db, not only the nth one
2- pattern will be matched even if it is not ending with a new line

So, tried to add \n at end of pattern to fix issue 2:
Code:
sed "s%system /path1/file1 file1\n%&\n    data /path2/file2 file2%" -i data.db

Result is pattern will not be replaced at all

and to fix issue 1, I tried the following with and without the -i:
Code:
sed "0,%system /path1/file1 file1%s%system /path1/file1 file1%&\n    data /path2/file2 file2%" [-i] data.db

No output error, but pattern is not matched

Any help please even if it is with another command
Difficulty seems to be caused by the / and spaces in my patterns!
# 2  
Old 09-13-2012
Code:
pattern="system /path1/file1 file1"
new_pattern=" data /path2/file2 file2"
n=3
awk '$0==patt{which++;if(which==n)$0=$0 RS repl}1' patt="$pattern" repl="$new_pattern" n=$n data.db

Replace value of n as per your requirement.
This User Gave Thanks to elixir_sinari For This Post:
Phil3759
# 3  
Old 09-13-2012
Thank you but it did not work
I just made n=1
Output was the content of my data.db file in terminal
and the file data.db was not edited
Smilie
# 4  
Old 09-13-2012
data.db will not be edited by that command (as opposed to that done by the -i switch of sed). You'll need to redirect the output of that command in a temporary file and then, rename that temporary file to data.db. Was the first occurrence of that pattern replaced by the replacement string in the terminal output?

It would help to post a representative sample of data.db. Also, mention the output produced by that command on this sample and the expected output.
Last edited by elixir_sinari; 09-13-2012 at 07:16 AM..
This User Gave Thanks to elixir_sinari For This Post:
Phil3759
# 5  
Old 09-13-2012
Quote:
Originally Posted by elixir_sinari
data.db will not be edited by that command (as opposed to that done by the -i switch of sed). You'll need to redirect the output of that command in a temporary file and then, rename that temporary file to data.db. Was the first occurrence of that pattern replaced by the replacement string in the terminal output?

It would help to post a representative sample of data.db. Also, mention the output produced by that command on this sample and the expected output.
Ah, I see
No way to see in terminal as data.db contents are too long
I redirected to a text file with this command:
Code:
pattern="system /path1/file1 file1"
new_pattern=" data /path2/file2 file2"
n=3
awk '$0==patt{which++;if(which==n)$0=$0 RS repl}1' patt="$pattern" repl="$new_pattern" n=$n data.db >test.txt

The output test.txt file has exactly same contents as original data.db, binary matching. So, the patetrn was not replaced Smilie

---------- Post updated at 12:21 PM ---------- Previous update was at 12:20 PM ----------

Ok, I will post details of files in code
# 6  
Old 09-13-2012
For your info:
Code:
$ cat data.db
HHOOIOIOI
system /path1/file1 file1
          system /path1/file1 file1
/system/path
system /path1/file1 file1
dfdfdf
dfdffffffffffff
dfdf
system /path1/file1 file1

$ pattern="system /path1/file1 file1"
$ new_pattern=" data /path2/file2 file2"
$ n=1

$ awk '$0==patt{which++;if(which==n)$0=$0 RS repl}1' patt="$pattern" repl="$new_pattern" n=$n data.db
HHOOIOIOI
system /path1/file1 file1
 data /path2/file2 file2
          system /path1/file1 file1
/system/path
system /path1/file1 file1
dfdfdf
dfdffffffffffff
dfdf
system /path1/file1 file1

Is your actual pattern surrounded by blanks on either side? Do you want to match such lines?
This User Gave Thanks to elixir_sinari For This Post:
Phil3759
# 7  
Old 09-13-2012
You got it right

pattern can sometimes be surrounded by white spaces
pattern=" system /path1/file1 file1 "
but sometimes only:

pattern="system /path1/file1 file1"

and sometimes a tab space
Code:
pattern="	system /path1/file1 file1"

correcting the spaces in $pattern fixed it, many thanks Smilie

However, it would be great if I can match those before/after spaces and tab

I am posting a file sample...
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