[unix-history] / usr / lib / learn / editor / L36.1a

#print
So far all the special characters in the substitute command
have been used in the left-hand expression, the one that
is looked for in the line as it exists before the change.
None of these characters are meaningful in the right-hand
expression; for example,
  s/ab/a./
turn "ab" into "a." just as if "." were an ordinary letter.
But there is one character that is special on the right
side of a substitution, which is '&'.  The ampersand
is replaced by whatever text is being replaced.  In
  s/the/&m/
the string "the" is turned into "them" because the '&' is
replaced by "the".
In this directory there is a file 'text'; on the third line,
change the word 'dog' into 'dogs'; then rewrite the file
and say "ready".
#create Ref
cat
mouse
dogs
rat
#create text
cat
mouse
dog
rat
#user
#cmp text Ref
#log
#next
37.1a 10
37.2a 6
Commit	Line	Data
fed84c9b TL	1	#print
	2	So far all the special characters in the substitute command
	3	have been used in the left-hand expression, the one that
	4	is looked for in the line as it exists before the change.
	5	None of these characters are meaningful in the right-hand
	6	expression; for example,
	7	s/ab/a./
	8	turn "ab" into "a." just as if "." were an ordinary letter.
	9	But there is one character that is special on the right
	10	side of a substitution, which is '&'. The ampersand
	11	is replaced by whatever text is being replaced. In
	12	s/the/&m/
	13	the string "the" is turned into "them" because the '&' is
	14	replaced by "the".
	15	In this directory there is a file 'text'; on the third line,
	16	change the word 'dog' into 'dogs'; then rewrite the file
	17	and say "ready".
	18	#create Ref
	19	cat
	20	mouse
	21	dogs
	22	rat
	23	#create text
	24	cat
	25	mouse
	26	dog
	27	rat
	28	#user
	29	#cmp text Ref
	30	#log
	31	#next
	32	37.1a 10
	33	37.2a 6