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