sed, a Streamlined Editor.
preface:Sed is a streamlined noninteractive editor.It can edit a file or data, and it just modify the output, but not modify the originally files.
Format of sed: $sed 'command' filename.
Command Functions:
a:Appends one or more lines of text to the current line.
c:Changes (replaces) text in the current line with new text.
d:Deletes lines.
e:more than one command.
i:Inserts text above the current line.
h:Copies the contents of the pattern space to a holding buffer.
H:Appends the contents of the pattern space to a holding buffer.
g:Gets what is in the holding buffer and copies it into the pattern buffer, overwriting what was there.
G:Gets what is in the holding buffer and copies it into the pattern buffer, appending to what was there.
l:Lists nonprinting characters.
p:Prints lines.
n:Reads the next input line and starts processing the newline with the next command rather than the first command.
s:Substitutes one string for another.
q:Quits or exits sed.rReads lines from a file.
!:Applies the command to all lines except the selected ones.
Substitution Flags:
g:Globally substitutes on a line.
p:Prints lines.
w:Writes lines out to a file.
x:Exchanges contents of the holding buffer with the pattern space.
y:Translates one character to another (cannot use regular expression metacharacters with y).
1)$sed '1,3p' myfile
it will prints all lines of your file.
2)$sed -n '1,3p' myfile
it will prints 1-3 lines of the file.
3)$sed '1,3d' myfile
it will deletes the lines from 1 to 3 of your file.
4)$sed '/Tom/d' datafile
it will deletes the line contains /Tom/ pattern.
5)$sed '/Tom/!d' datafile
it will deletes the line dont contains /Tom/ pattern.
6)$sed 's/12345//g datafile
it will change the 12345 to space of nothing with the goalble range.
7)$sed '3,$d' datafile
8)$sed -e '1,3d' -e 's/Hemenway/Jones/' datafile
9)$ sed '/Suan/r newfile' datafile
ps: r means read newfile.
10)$sed '/Lewis/{s/Lewis/Joseph/;q;}' datafile