using awk to comment out lines to the end of file

Shell Programming and Scripting
1

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

2

Should be something like this:

awk '/^c/{f=1}f{$0 = "#" $0}{print}' file
3

Thanks that works well

May I ask where can read on reference for

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

4 
awk '/^c/{f=1}     ## If the first character of the line is "c" set f = 1
  f {$0 = "#" $0}  ## if f is not equal to 0, add "#" to beginning of line
  {print}          ## print every line
' file
5 
sed '/c/,$s/^/#/' yourfile
6 
awk '/^c/,eof{$0="#"$0}1' file