sed Option & Command & RE

nothing?

sed opting 'command' filename

command
a\      add  back
i\       insert front
d
h       copy pattern space to hold buffer 
H      add  pattern space to hold buffer 
g      反向 h
G     反向 H
-n    read next row and use next command    sed '\tony\' filename
r      file
w     file
s/RE/string/gp
g               
p                       print
x                       change pattern to  hold buffer
y                       change letter1 to letter2  (no RE)           sed '1,3y/abc/ABC' filename
option
-e    many edit
-n      
-f     file
-V    version

RE
^
$
.
*
[]
[^]
\(  \)
&      sed 's/love/**&**/p' filename
\<  \>
x\花括m\花括
x\花括m,\花括
x\花括m,n\花括