Linux command-sed

Sed:stream Editor for filtering and transforming text flow editor textbox

SED does not use the-I case, do not modify the source files, only the processing results are printed to the screen, using-I will be directly modified source files, is a dangerous practice, used in scripts to modify the configuration file, beginners do not recommend.

How to use sed:

Sed Range modified Print:

Direct Print File line fourth: Sed-n ' 4p ' path_to_file

Only delete the data from line fourth to the next row (including the next blank line) and print additional data: sed ' 4,/^$/d '/path_to_file

Data from line fourth to the next row is not printed (including the next blank line): Sed-n ' 4,/^$/!p '/path_to_file

Show only the fourth line to the next empty row of data (including the next blank line) do not delete only print these: sed ' 4,/^$/!d '/path_to_file

The first line that is matched by the pattern is started, and the line to the second pattern matches to the end of all rows in the middle:/pattern1/,/pattern2/

Sed parameters:

-N:--quiet,--silent: Silent mode no longer defaults to display the contents of the mode

-r:use extended Regular expressions in the script. Using an extended regular expression

SED replacement:

Sed-r ' s/regexp/replacement/g '/path_to_file:sed-r ' s/[[:space:]]+//g ' file removes whitespace from the beginning of the line

Sed search Merge instance: Cat/etc/inittab |sed-r ' s/^#//g;s/^[[:space:]]+//g;/^$/d ': Remove the # number at the beginning of the file Inittab file, the first white space character, and the blank line

SED modifies or removes a word in the range: Sed-i ' 2,3s/\<nameserver\>//g '/etc/resolv.conf:

Remove 2 to 3 rows of nameserver

sed modifier: g: Global substitution

I: Ignore character case

Sed back to Application:

Sed ' s#\ (pattern\) #\1xx#g ' file

sed other: A \string: Append a new line after the specified line, with the contents "string"

I \string: Adds a new line before the specified line, with the content "Srting"

Linux command-sed