Insert multiline text before the first matching line in a file

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up vote
3
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we want to add the following lines in log4j file

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB

but these lines must be before the first line that include the word - DatePattern , and no matter if line is with mark or not

#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

or

log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

note - in case DatePattern word apears couple times in file , then the three lines must be set only before the first line that include - DatePattern

example 1 ( expected output )

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB


#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

example 2 ( expected output )

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB


log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

text-processing awk sed logs perl

share|improve this question

edited 7 hours ago

don_crissti

46k15119151

asked 8 hours ago

yael

1,787940

add a comment | 

up vote
3
down vote

favorite

we want to add the following lines in log4j file

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB

but these lines must be before the first line that include the word - DatePattern , and no matter if line is with mark or not

#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

or

log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

note - in case DatePattern word apears couple times in file , then the three lines must be set only before the first line that include - DatePattern

example 1 ( expected output )

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB


#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

example 2 ( expected output )

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB


log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

text-processing awk sed logs perl

share|improve this question

edited 7 hours ago

don_crissti

46k15119151

asked 8 hours ago

yael

1,787940

add a comment | 

up vote
3
down vote

favorite

up vote
3
down vote

favorite

we want to add the following lines in log4j file

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB

but these lines must be before the first line that include the word - DatePattern , and no matter if line is with mark or not

#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

or

log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

note - in case DatePattern word apears couple times in file , then the three lines must be set only before the first line that include - DatePattern

example 1 ( expected output )

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB


#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

example 2 ( expected output )

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB


log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

text-processing awk sed logs perl

share|improve this question

edited 7 hours ago

don_crissti

46k15119151

asked 8 hours ago

yael

1,787940

we want to add the following lines in log4j file

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB

but these lines must be before the first line that include the word - DatePattern , and no matter if line is with mark or not

#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

or

log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

note - in case DatePattern word apears couple times in file , then the three lines must be set only before the first line that include - DatePattern

example 1 ( expected output )

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB


#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

example 2 ( expected output )

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB


log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

text-processing awk sed logs perl

share|improve this question

edited 7 hours ago

don_crissti

46k15119151

asked 8 hours ago

yael

1,787940

share|improve this question

share|improve this question

edited 7 hours ago

don_crissti

46k15119151

edited 7 hours ago

don_crissti

46k15119151

edited 7 hours ago

don_crissti

46k15119151

46k15119151

asked 8 hours ago

yael

1,787940

asked 8 hours ago

yael

1,787940

asked 8 hours ago

yael

1,787940

1,787940

add a comment | 

add a comment | 

4 Answers
4

active

oldest

votes

up vote
2
down vote



accepted

If I understand your question correctly you merely want to replace this line:

log4j.appender.DRFA.DatePattern=.yyyy-MM-dd
-or-
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

With these lines:

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB
log4j.appender.DRFA.DatePattern=.yyyy-MM-dd
-or-
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

This GNU sed command can do this:

$ sed -i 's/(.*appender.DRFA.DatePattern=.*)/log4j.appender.DRFA=org.apache.log4j.RollingFileAppendernlog4j.appender.DRFA.MaxBackupIndex=100nlog4j.appender.DRFA.MaxFileSize=10MBnnn1/' log4j.properties

With respect to the duplicating of lines. You're not going to have this appender defined more than 1 time:

appender.DRFA.DatePattern

Therefore we can look more explicitly for this occurrence, rather than the DatePattern line that you're looking for.

Example run

Here's a sample file that has just this line in it:

$ cat log4j.properties
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

Run the sed command above against this file:

$ cat log4j.properties
log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

share|improve this answer

edited 6 hours ago

Kusalananda

100k13199310

answered 7 hours ago

slm♦

232k65479648

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  @yael - I updated the answer so that it includes them now.
  – slm♦
  7 hours ago
  
  

  
  
  
  

add a comment | 

up vote
5
down vote

Using awk:

awk 'done != 1 && /DatePattern/ 
 print "log4j.appender.DRFA=org.apache.log4j.RollingFileAppender"
 print "log4j.appender.DRFA.MaxBackupIndex=100"
 print "log4j.appender.DRFA.MaxFileSize=10MB"
 done = 1
 1' file >newfile && mv newfile file

This would print the three lines when the first match of DatePattern occurs in the file. The flag done is then set to 1 which stops the lines from being printed again. The trailing 1 at the very end causes every line in the in-data to be printed.

If you want empty lines in the output after the three lines, add nn to the end of the last string.

The output is written to newfile and if awk did not encounter any strange errors, the original is then replaced by this once the awk process terminates.

share|improve this answer

edited 8 hours ago

answered 8 hours ago

Kusalananda

100k13199310

• 
  
  
  

  
  

  
  
  
  
  
  

  
  good solution , but I prefer to update the file itself like "sed -i" and not copy the file to the source file for update , is it possible with awk ?
  – yael
  8 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @yael A standard redirection and mv. See updated answer. Not even GNU awk has an in-place editing option. It's not something that awk program usually do.
  – Kusalananda
  8 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  GNU awk has it...
  – don_crissti
  7 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @don_crissti :-) That's an extension, even to GNU awk.
  – Kusalananda
  7 hours ago
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  Sure but that doesn't change the fact that it exists... Anyway, +1 for answering the actual question here...
  – don_crissti
  7 hours ago
  

  
  
  
  

add a comment | 

up vote
3
down vote

Using GNU sed you may approach it this way also:

sed -i -e '
 /DatePattern/!b

 i
log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB

 :a;n;$!ba
' input.file

And if you are sure that the DatePattern cannot be on the last line of the file, then you could do this also:

sed -i -e '
 /DatePattern/!b
 r file2add.txt
 N;:a;n;$!ba
' input.file

where you put all the lines to be added into a file, say file2add.txt. Note: with this method, you don't put trailing backslashes in the file file2add.txt.

share|improve this answer

answered 7 hours ago

Rakesh Sharma

2933

• 
  
  
  

  
  

  
  
  
  
  
  

  
  Yes, those are both proper ways to do it with sed. Future visitors should keep in mind that i requires any embedded backslashes to be escaped.
  – don_crissti
  7 hours ago
  

  
  
  
  

add a comment | 

up vote
2
down vote

Since you tagged this query with perl also, so here goes one obvious way:

perl -pi -e '
 print <<EOF if /DatePattern/ && !$seen++;
log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB
EOF
' input.file

Note: The added text mustn't contain the standalone string EOF on a line by itself. The backslashing of the heredoc is necessary , lest any variables get expanded .

If you cannot be sure of the above constraints in the text to add, then do this:

perl -pi -e '
 next if !/DatePattern/ || $seen++;
 open my $fh, "<", "file2add.txt" or die "Could not open file for reading:$!n";
 $_ = join "", <$fh>, $_;
' input.file

share|improve this answer

answered 6 hours ago

Rakesh Sharma

2933

add a comment | 

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4 Answers
4

active

oldest

votes

4 Answers
4

active

oldest

votes

active

oldest

votes

active

oldest

votes

up vote
2
down vote



accepted

If I understand your question correctly you merely want to replace this line:

log4j.appender.DRFA.DatePattern=.yyyy-MM-dd
-or-
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

With these lines:

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB
log4j.appender.DRFA.DatePattern=.yyyy-MM-dd
-or-
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

This GNU sed command can do this:

$ sed -i 's/(.*appender.DRFA.DatePattern=.*)/log4j.appender.DRFA=org.apache.log4j.RollingFileAppendernlog4j.appender.DRFA.MaxBackupIndex=100nlog4j.appender.DRFA.MaxFileSize=10MBnnn1/' log4j.properties

With respect to the duplicating of lines. You're not going to have this appender defined more than 1 time:

appender.DRFA.DatePattern

Therefore we can look more explicitly for this occurrence, rather than the DatePattern line that you're looking for.

Example run

Here's a sample file that has just this line in it:

$ cat log4j.properties
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

Run the sed command above against this file:

$ cat log4j.properties
log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

share|improve this answer

edited 6 hours ago

Kusalananda

100k13199310

answered 7 hours ago

slm♦

232k65479648

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  @yael - I updated the answer so that it includes them now.
  – slm♦
  7 hours ago
  
  

  
  
  
  

add a comment | 

up vote
2
down vote



accepted

If I understand your question correctly you merely want to replace this line:

log4j.appender.DRFA.DatePattern=.yyyy-MM-dd
-or-
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

With these lines:

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB
log4j.appender.DRFA.DatePattern=.yyyy-MM-dd
-or-
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

This GNU sed command can do this:

$ sed -i 's/(.*appender.DRFA.DatePattern=.*)/log4j.appender.DRFA=org.apache.log4j.RollingFileAppendernlog4j.appender.DRFA.MaxBackupIndex=100nlog4j.appender.DRFA.MaxFileSize=10MBnnn1/' log4j.properties

With respect to the duplicating of lines. You're not going to have this appender defined more than 1 time:

appender.DRFA.DatePattern

Therefore we can look more explicitly for this occurrence, rather than the DatePattern line that you're looking for.

Example run

Here's a sample file that has just this line in it:

$ cat log4j.properties
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

Run the sed command above against this file:

$ cat log4j.properties
log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

share|improve this answer

edited 6 hours ago

Kusalananda

100k13199310

answered 7 hours ago

slm♦

232k65479648

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  @yael - I updated the answer so that it includes them now.
  – slm♦
  7 hours ago
  
  

  
  
  
  

add a comment | 

up vote
2
down vote



accepted

up vote
2
down vote



accepted

If I understand your question correctly you merely want to replace this line:

log4j.appender.DRFA.DatePattern=.yyyy-MM-dd
-or-
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

With these lines:

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB
log4j.appender.DRFA.DatePattern=.yyyy-MM-dd
-or-
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

This GNU sed command can do this:

$ sed -i 's/(.*appender.DRFA.DatePattern=.*)/log4j.appender.DRFA=org.apache.log4j.RollingFileAppendernlog4j.appender.DRFA.MaxBackupIndex=100nlog4j.appender.DRFA.MaxFileSize=10MBnnn1/' log4j.properties

With respect to the duplicating of lines. You're not going to have this appender defined more than 1 time:

appender.DRFA.DatePattern

Therefore we can look more explicitly for this occurrence, rather than the DatePattern line that you're looking for.

Example run

Here's a sample file that has just this line in it:

$ cat log4j.properties
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

Run the sed command above against this file:

$ cat log4j.properties
log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

share|improve this answer

edited 6 hours ago

Kusalananda

100k13199310

answered 7 hours ago

slm♦

232k65479648

If I understand your question correctly you merely want to replace this line:

log4j.appender.DRFA.DatePattern=.yyyy-MM-dd
-or-
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

With these lines:

log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB
log4j.appender.DRFA.DatePattern=.yyyy-MM-dd
-or-
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

This GNU sed command can do this:

$ sed -i 's/(.*appender.DRFA.DatePattern=.*)/log4j.appender.DRFA=org.apache.log4j.RollingFileAppendernlog4j.appender.DRFA.MaxBackupIndex=100nlog4j.appender.DRFA.MaxFileSize=10MBnnn1/' log4j.properties

With respect to the duplicating of lines. You're not going to have this appender defined more than 1 time:

appender.DRFA.DatePattern

Therefore we can look more explicitly for this occurrence, rather than the DatePattern line that you're looking for.

Example run

Here's a sample file that has just this line in it:

$ cat log4j.properties
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

Run the sed command above against this file:

$ cat log4j.properties
log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB
#log4j.appender.DRFA.DatePattern=.yyyy-MM-dd

share|improve this answer

edited 6 hours ago

Kusalananda

100k13199310

answered 7 hours ago

slm♦

232k65479648

share|improve this answer

share|improve this answer

edited 6 hours ago

Kusalananda

100k13199310

edited 6 hours ago

Kusalananda

100k13199310

edited 6 hours ago

Kusalananda

100k13199310

100k13199310

answered 7 hours ago

slm♦

232k65479648

answered 7 hours ago

slm♦

232k65479648

answered 7 hours ago

slm♦

232k65479648

232k65479648

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  @yael - I updated the answer so that it includes them now.
  – slm♦
  7 hours ago
  
  

  
  
  
  

add a comment | 

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  @yael - I updated the answer so that it includes them now.
  – slm♦
  7 hours ago
  
  

  
  
  
  

1

1

@yael - I updated the answer so that it includes them now.
– slm♦
7 hours ago

@yael - I updated the answer so that it includes them now.
– slm♦
7 hours ago

add a comment | 

up vote
5
down vote

Using awk:

awk 'done != 1 && /DatePattern/ 
 print "log4j.appender.DRFA=org.apache.log4j.RollingFileAppender"
 print "log4j.appender.DRFA.MaxBackupIndex=100"
 print "log4j.appender.DRFA.MaxFileSize=10MB"
 done = 1
 1' file >newfile && mv newfile file

This would print the three lines when the first match of DatePattern occurs in the file. The flag done is then set to 1 which stops the lines from being printed again. The trailing 1 at the very end causes every line in the in-data to be printed.

If you want empty lines in the output after the three lines, add nn to the end of the last string.

The output is written to newfile and if awk did not encounter any strange errors, the original is then replaced by this once the awk process terminates.

share|improve this answer

edited 8 hours ago

answered 8 hours ago

Kusalananda

100k13199310

• 
  
  
  

  
  

  
  
  
  
  
  

  
  good solution , but I prefer to update the file itself like "sed -i" and not copy the file to the source file for update , is it possible with awk ?
  – yael
  8 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @yael A standard redirection and mv. See updated answer. Not even GNU awk has an in-place editing option. It's not something that awk program usually do.
  – Kusalananda
  8 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  GNU awk has it...
  – don_crissti
  7 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @don_crissti :-) That's an extension, even to GNU awk.
  – Kusalananda
  7 hours ago
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  Sure but that doesn't change the fact that it exists... Anyway, +1 for answering the actual question here...
  – don_crissti
  7 hours ago
  

  
  
  
  

add a comment | 

up vote
5
down vote

Using awk:

awk 'done != 1 && /DatePattern/ 
 print "log4j.appender.DRFA=org.apache.log4j.RollingFileAppender"
 print "log4j.appender.DRFA.MaxBackupIndex=100"
 print "log4j.appender.DRFA.MaxFileSize=10MB"
 done = 1
 1' file >newfile && mv newfile file

This would print the three lines when the first match of DatePattern occurs in the file. The flag done is then set to 1 which stops the lines from being printed again. The trailing 1 at the very end causes every line in the in-data to be printed.

If you want empty lines in the output after the three lines, add nn to the end of the last string.

The output is written to newfile and if awk did not encounter any strange errors, the original is then replaced by this once the awk process terminates.

share|improve this answer

edited 8 hours ago

answered 8 hours ago

Kusalananda

100k13199310

• 
  
  
  

  
  

  
  
  
  
  
  

  
  good solution , but I prefer to update the file itself like "sed -i" and not copy the file to the source file for update , is it possible with awk ?
  – yael
  8 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @yael A standard redirection and mv. See updated answer. Not even GNU awk has an in-place editing option. It's not something that awk program usually do.
  – Kusalananda
  8 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  GNU awk has it...
  – don_crissti
  7 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @don_crissti :-) That's an extension, even to GNU awk.
  – Kusalananda
  7 hours ago
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  Sure but that doesn't change the fact that it exists... Anyway, +1 for answering the actual question here...
  – don_crissti
  7 hours ago
  

  
  
  
  

add a comment | 

up vote
5
down vote

up vote
5
down vote

Using awk:

awk 'done != 1 && /DatePattern/ 
 print "log4j.appender.DRFA=org.apache.log4j.RollingFileAppender"
 print "log4j.appender.DRFA.MaxBackupIndex=100"
 print "log4j.appender.DRFA.MaxFileSize=10MB"
 done = 1
 1' file >newfile && mv newfile file

This would print the three lines when the first match of DatePattern occurs in the file. The flag done is then set to 1 which stops the lines from being printed again. The trailing 1 at the very end causes every line in the in-data to be printed.

If you want empty lines in the output after the three lines, add nn to the end of the last string.

The output is written to newfile and if awk did not encounter any strange errors, the original is then replaced by this once the awk process terminates.

share|improve this answer

edited 8 hours ago

answered 8 hours ago

Kusalananda

100k13199310

Using awk:

awk 'done != 1 && /DatePattern/ 
 print "log4j.appender.DRFA=org.apache.log4j.RollingFileAppender"
 print "log4j.appender.DRFA.MaxBackupIndex=100"
 print "log4j.appender.DRFA.MaxFileSize=10MB"
 done = 1
 1' file >newfile && mv newfile file

This would print the three lines when the first match of DatePattern occurs in the file. The flag done is then set to 1 which stops the lines from being printed again. The trailing 1 at the very end causes every line in the in-data to be printed.

If you want empty lines in the output after the three lines, add nn to the end of the last string.

The output is written to newfile and if awk did not encounter any strange errors, the original is then replaced by this once the awk process terminates.

share|improve this answer

edited 8 hours ago

answered 8 hours ago

Kusalananda

100k13199310

share|improve this answer

share|improve this answer

edited 8 hours ago

edited 8 hours ago

edited 8 hours ago

answered 8 hours ago

Kusalananda

100k13199310

answered 8 hours ago

Kusalananda

100k13199310

answered 8 hours ago

Kusalananda

100k13199310

100k13199310

• 
  
  
  

  
  

  
  
  
  
  
  

  
  good solution , but I prefer to update the file itself like "sed -i" and not copy the file to the source file for update , is it possible with awk ?
  – yael
  8 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @yael A standard redirection and mv. See updated answer. Not even GNU awk has an in-place editing option. It's not something that awk program usually do.
  – Kusalananda
  8 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  GNU awk has it...
  – don_crissti
  7 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @don_crissti :-) That's an extension, even to GNU awk.
  – Kusalananda
  7 hours ago
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  Sure but that doesn't change the fact that it exists... Anyway, +1 for answering the actual question here...
  – don_crissti
  7 hours ago
  

  
  
  
  

add a comment | 

• 
  
  
  

  
  

  
  
  
  
  
  

  
  good solution , but I prefer to update the file itself like "sed -i" and not copy the file to the source file for update , is it possible with awk ?
  – yael
  8 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @yael A standard redirection and mv. See updated answer. Not even GNU awk has an in-place editing option. It's not something that awk program usually do.
  – Kusalananda
  8 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  GNU awk has it...
  – don_crissti
  7 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @don_crissti :-) That's an extension, even to GNU awk.
  – Kusalananda
  7 hours ago
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  Sure but that doesn't change the fact that it exists... Anyway, +1 for answering the actual question here...
  – don_crissti
  7 hours ago
  

  
  
  
  

good solution , but I prefer to update the file itself like "sed -i" and not copy the file to the source file for update , is it possible with awk ?
– yael
8 hours ago

good solution , but I prefer to update the file itself like "sed -i" and not copy the file to the source file for update , is it possible with awk ?
– yael
8 hours ago

@yael A standard redirection and mv. See updated answer. Not even GNU awk has an in-place editing option. It's not something that awk program usually do.
– Kusalananda
8 hours ago

@yael A standard redirection and mv. See updated answer. Not even GNU awk has an in-place editing option. It's not something that awk program usually do.
– Kusalananda
8 hours ago

1

1

GNU awk has it...
– don_crissti
7 hours ago

GNU awk has it...
– don_crissti
7 hours ago

@don_crissti :-) That's an extension, even to GNU awk.
– Kusalananda
7 hours ago

@don_crissti :-) That's an extension, even to GNU awk.
– Kusalananda
7 hours ago

1

1

Sure but that doesn't change the fact that it exists... Anyway, +1 for answering the actual question here...
– don_crissti
7 hours ago

Sure but that doesn't change the fact that it exists... Anyway, +1 for answering the actual question here...
– don_crissti
7 hours ago

add a comment | 

up vote
3
down vote

Using GNU sed you may approach it this way also:

sed -i -e '
 /DatePattern/!b

 i
log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB

 :a;n;$!ba
' input.file

And if you are sure that the DatePattern cannot be on the last line of the file, then you could do this also:

sed -i -e '
 /DatePattern/!b
 r file2add.txt
 N;:a;n;$!ba
' input.file

where you put all the lines to be added into a file, say file2add.txt. Note: with this method, you don't put trailing backslashes in the file file2add.txt.

share|improve this answer

answered 7 hours ago

Rakesh Sharma

2933

• 
  
  
  

  
  

  
  
  
  
  
  

  
  Yes, those are both proper ways to do it with sed. Future visitors should keep in mind that i requires any embedded backslashes to be escaped.
  – don_crissti
  7 hours ago
  

  
  
  
  

add a comment | 

up vote
3
down vote

Using GNU sed you may approach it this way also:

sed -i -e '
 /DatePattern/!b

 i
log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB

 :a;n;$!ba
' input.file

And if you are sure that the DatePattern cannot be on the last line of the file, then you could do this also:

sed -i -e '
 /DatePattern/!b
 r file2add.txt
 N;:a;n;$!ba
' input.file

where you put all the lines to be added into a file, say file2add.txt. Note: with this method, you don't put trailing backslashes in the file file2add.txt.

share|improve this answer

answered 7 hours ago

Rakesh Sharma

2933

• 
  
  
  

  
  

  
  
  
  
  
  

  
  Yes, those are both proper ways to do it with sed. Future visitors should keep in mind that i requires any embedded backslashes to be escaped.
  – don_crissti
  7 hours ago
  

  
  
  
  

add a comment | 

up vote
3
down vote

up vote
3
down vote

Using GNU sed you may approach it this way also:

sed -i -e '
 /DatePattern/!b

 i
log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB

 :a;n;$!ba
' input.file

And if you are sure that the DatePattern cannot be on the last line of the file, then you could do this also:

sed -i -e '
 /DatePattern/!b
 r file2add.txt
 N;:a;n;$!ba
' input.file

where you put all the lines to be added into a file, say file2add.txt. Note: with this method, you don't put trailing backslashes in the file file2add.txt.

share|improve this answer

answered 7 hours ago

Rakesh Sharma

2933

Using GNU sed you may approach it this way also:

sed -i -e '
 /DatePattern/!b

 i
log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB

 :a;n;$!ba
' input.file

And if you are sure that the DatePattern cannot be on the last line of the file, then you could do this also:

sed -i -e '
 /DatePattern/!b
 r file2add.txt
 N;:a;n;$!ba
' input.file

where you put all the lines to be added into a file, say file2add.txt. Note: with this method, you don't put trailing backslashes in the file file2add.txt.

share|improve this answer

answered 7 hours ago

Rakesh Sharma

2933

share|improve this answer

share|improve this answer

answered 7 hours ago

Rakesh Sharma

2933

answered 7 hours ago

Rakesh Sharma

2933

answered 7 hours ago

Rakesh Sharma

2933

2933

• 
  
  
  

  
  

  
  
  
  
  
  

  
  Yes, those are both proper ways to do it with sed. Future visitors should keep in mind that i requires any embedded backslashes to be escaped.
  – don_crissti
  7 hours ago
  

  
  
  
  

add a comment | 

• 
  
  
  

  
  

  
  
  
  
  
  

  
  Yes, those are both proper ways to do it with sed. Future visitors should keep in mind that i requires any embedded backslashes to be escaped.
  – don_crissti
  7 hours ago
  

  
  
  
  

Yes, those are both proper ways to do it with sed. Future visitors should keep in mind that i requires any embedded backslashes to be escaped.
– don_crissti
7 hours ago

Yes, those are both proper ways to do it with sed. Future visitors should keep in mind that i requires any embedded backslashes to be escaped.
– don_crissti
7 hours ago

add a comment | 

up vote
2
down vote

Since you tagged this query with perl also, so here goes one obvious way:

perl -pi -e '
 print <<EOF if /DatePattern/ && !$seen++;
log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB
EOF
' input.file

Note: The added text mustn't contain the standalone string EOF on a line by itself. The backslashing of the heredoc is necessary , lest any variables get expanded .

If you cannot be sure of the above constraints in the text to add, then do this:

perl -pi -e '
 next if !/DatePattern/ || $seen++;
 open my $fh, "<", "file2add.txt" or die "Could not open file for reading:$!n";
 $_ = join "", <$fh>, $_;
' input.file

share|improve this answer

answered 6 hours ago

Rakesh Sharma

2933

add a comment | 

up vote
2
down vote

Since you tagged this query with perl also, so here goes one obvious way:

perl -pi -e '
 print <<EOF if /DatePattern/ && !$seen++;
log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB
EOF
' input.file

Note: The added text mustn't contain the standalone string EOF on a line by itself. The backslashing of the heredoc is necessary , lest any variables get expanded .

If you cannot be sure of the above constraints in the text to add, then do this:

perl -pi -e '
 next if !/DatePattern/ || $seen++;
 open my $fh, "<", "file2add.txt" or die "Could not open file for reading:$!n";
 $_ = join "", <$fh>, $_;
' input.file

share|improve this answer

answered 6 hours ago

Rakesh Sharma

2933

add a comment | 

up vote
2
down vote

up vote
2
down vote

Since you tagged this query with perl also, so here goes one obvious way:

perl -pi -e '
 print <<EOF if /DatePattern/ && !$seen++;
log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB
EOF
' input.file

Note: The added text mustn't contain the standalone string EOF on a line by itself. The backslashing of the heredoc is necessary , lest any variables get expanded .

If you cannot be sure of the above constraints in the text to add, then do this:

perl -pi -e '
 next if !/DatePattern/ || $seen++;
 open my $fh, "<", "file2add.txt" or die "Could not open file for reading:$!n";
 $_ = join "", <$fh>, $_;
' input.file

share|improve this answer

answered 6 hours ago

Rakesh Sharma

2933

Since you tagged this query with perl also, so here goes one obvious way:

perl -pi -e '
 print <<EOF if /DatePattern/ && !$seen++;
log4j.appender.DRFA=org.apache.log4j.RollingFileAppender
log4j.appender.DRFA.MaxBackupIndex=100
log4j.appender.DRFA.MaxFileSize=10MB
EOF
' input.file

Note: The added text mustn't contain the standalone string EOF on a line by itself. The backslashing of the heredoc is necessary , lest any variables get expanded .

If you cannot be sure of the above constraints in the text to add, then do this:

perl -pi -e '
 next if !/DatePattern/ || $seen++;
 open my $fh, "<", "file2add.txt" or die "Could not open file for reading:$!n";
 $_ = join "", <$fh>, $_;
' input.file

share|improve this answer

answered 6 hours ago

Rakesh Sharma

2933

share|improve this answer

share|improve this answer

answered 6 hours ago

Rakesh Sharma

2933

answered 6 hours ago

Rakesh Sharma

2933

answered 6 hours ago

Rakesh Sharma

2933

2933

add a comment | 

add a comment | 

 

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