I want to delete a blank line only if this one is after the line of my pattern using sed or awk for example if I have
G
O TO P999-ERREUR
END-IF.
the pattern in this case is G
I want to have this output
G
O TO P999-ERREUR
END-IF.
-
better edit to show your attempts and format properlyfedorqui– fedorqui2015-08-12 10:03:26 +00:00Commented Aug 12, 2015 at 10:03
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4 Answers
This will do the trick:
$ awk -v n=-2 'NR==n+1 && !NF{next} /G/ {n=NR}1' file
G
O TO P999-ERREUR
END-IF.
Explanation:
-v n=-2 # Set n=-2 before the script is run to avoid not printing the first line
NR == n+1 # If the current line number is equal to the matching line + 1
&& !NF # And the line is empty
{next} # Skip the line (don't print it)
/G/ # The regular expression to match
{n = NR} # Save the current line number in the variable n
1 # Truthy value used a shorthand to print every (non skipped) line
Comments
Using sed
sed '/GG/{N;s/\n$//}' file
If it sees GG, gets the next line, removes the newline between them if the next line is empty.
Note this will only remove one blank line after, and the line must be blank i.e not spaces or tabs.
Comments
This might work for you (GNU sed):
sed -r 'N;s/(G.*)\n\s*$/\1/;P;D' file
Keep a moving window of two lines throughout the length of the file and remove a newline (and any whitespace) if it follows the intended pattern.
Comments
Using ex (edit in-place):
ex +'/G/j' -cwq foo.txt
or print to the standard output (from file or stdin):
ex -s +'/GG/j|%p|q!' file_or_/dev/stdin
where:
/GG/j- joins the next line when the pattern is found%p- prints the bufferq!- quits
For conditional checking (if there is a blank line), try:
ex -s +'%s/^\(G\)\n/\1/' +'%p|q!' file_or_/dev/stdin
1 Comment
kenorb
You can replace
foo.txt with /dev/stdin. However it doesn't check for the blank line, let me check that.