using awk to comment out lines to the end of file

phamp008 · #1 (**permalink**) 07-04-2009

Hello,

I have a file as follow

a
b
c
c
d
d
e

I would like to write a awk command to insert # from the first occurence of
"c" to the end of the files.
OUTPUT should be like this

a
b
#c
#c
#d
#d
#e

I kept getting error while attempting to use break

awk ' if ( $1 ~ /^c/ ) { beginline = NR ; break } '

Greatly appreciate your comment

Franklin52 · #2 (**permalink**) 07-04-2009

Should be something like this:

Code:

awk '/^c/{f=1}f{$0 = "#" $0}{print}' file

phamp008 · #3 (**permalink**) 07-04-2009

Thanks that works well

May I ask where can read on reference for

f{$0 = "#" $0} ?

cfajohnson · #4 (**permalink**) 07-04-2009

Code:

awk '/^c/{f=1}     ## If the first character of the line is "c" set f = 1
  f {$0 = "#" $0}  ## if f is not equal to 0, add "#" to beginning of line
  {print}          ## print every line
' file

summer_cherry · #5 (**permalink**) 07-05-2009

Code:

sed '/c/,$s/^/#/' yourfile

ghostdog74 · #6 (**permalink**) 07-05-2009

Code:

awk '/^c/,eof{$0="#"$0}1' file

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