usr/lib/learn/editor/L14.2a

#print
You can also use the "=" command to find out what
the 'current' line is.  Since the current line
is named '.', the appropriate command is
   .=
and so if you say
   3p
   .=
the second command will print '3'.  Since you should not
believe what I tell you without checking it, edit file
"doubt" and type the two commands above, which first
print line 3 (and incidentally set "." to that line) and
then ask what number "." is.  Then type w, q, ready.
#create doubt
you didn't have to print this line
you didn't have to print this line
to err is human, to really foul things up takes a computer
you didn't have to print this line
you didn't have to print this line
#copyout
#user
#uncopyout
grep 3 .ocopy >dev/null
#log
#next
14.2b 5