Reproduced Shell deletes scripts for various annotations

Transferred from: http://www.cppblog.com/zhangyq/archive/2010/10/08/127915.html

1.txt content:
File content
Aabbcc<<<comment Part 1
Abcdefg
Hilkdifdfdf
Mmmmmmmm
Eeeeeeeeeeeeee
Comment Part 2>>>
Ddeeff
SED-E ": Begin; /<<</,/>>>/{/>>>/! { $! {N; b begin}; }; s/<<<.*>>>//; };" 1.txt
File content
Aabbcc
Ddeeff

• The first curly brace {} Represents the beginning of the command block, like the C syntax, which is no longer spoken.

• :begin, this is a label, man is called the label, which is the jump tag, for the B and T command, in this case, the B command is used.

• /<<</,/>>>/, this is an address range (Addresses), and the commands in the following {} are used only for content between the address ranges. Where the previous part of the comma is the start address, and the comma is followed by the end address, both are regular expressions. Because SED is "stream" line processing, the end address can be omitted, that is, if the end range of the address does not exist, it will be processed until the end of the file. The address range used in this example is mainly to reduce the amount of data processed, because although the processing of a row is extended to multiple rows with the n command, the string to be processed in buffer can be very long and inefficient if it is extended from the beginning of the file to <<< until it appears. So you can get the right result out of this processing range,

• Like what:

  $ sed -e ":begin; { />>>/! { $! { N; b begin }; }; s/<<<.*>>>/COMMENT/; };" testor$ sed -e "{:begin;  />>>/! { $! { N; b begin }; }; s/<<<.*>>>/COMMENT/; };" test

• />>>/!, >>> is to replace the end tag of the content, with the ! meaning that when a line is finished, if no end tag is found ...

• $!, which $ represents the end of the string in the regular, represents the last line of the file in the SED, and this sentence, combined with the previous sentence, means: If the end tag is not found in the bank and the currently scanned row is not the last line of the file.

• N;, after appending the contents of the next line (append) to the buffer (pattern), in our example, when the contents of this line are processed, it is aabbcc<<<comment part 1 executed here, and then the contents of the next line are put comment part 2>>> into the buffer, equivalent to "merge" into a row (the SED buffers contain only one line of content by default).

• b begin, since the end tag is still not found <<< (note that the previous buffer has not been processed), jump back here to the label begin and start the command again. If more than one line is spaced between the start and end tags, multiple jumps occur.

• s/<<<.*>>>/comment/; , finally, />>>/! No longer matches the success, that is, we have found the end tag, then use the S command to replace. If the start and end tags are on one line, they will go over the complex processing above and execute directly here

  If you want to delete the comment in the label C: Use the following command
  Sed-e ": Begin; { /\*\//! { $! {N; b begin}; }; s/\/\*.*\*\///; };" 2. txt
  2.txt content is as follows:
  file content
    aabbcc/*comment Part 1
  ABCDEFG
  hilkdifdfdf
  Mmmmmmmm
  Eeeeeeeeeeeeee
    Comment Part 2*/
    Ddeeff
  Execute command results as follows:
  file content
    AABBCC
    Ddeeff
   sed '/\/\*/{/\*\//d;:a; n;/\*\//d;ba};s,//.*, ' 2.txt will delete the AABBCC line above
  The above command is appropriate for annotating multiple lines, the code and Comment lines are not on one line, with sed-e ": Begin; { /\*\//! { $! {N; b begin}; }; s/\/\*.*\*\///; }; "causes a blank line to appear
  if the following is not a problem
  file content
    AABBCC
  /*comment Part 1
  ABCDEFG
  HILKDIFDFDF
  Mmmmmmmm
  Eeeeeeeeeeeeee
    Comment Part 2*/ddeeff
  perform sed-e ": Begin; { /\*\//! { $! {N; b begin}; }; s/\/\*.*\*\///; The result is
  file content
    AABBCC
   ddeeff
  But there is still a blank line, so if you want to remove the C comment with sed-e ": Begin; { /\*\//! { $! {N; b begin}; }; s/\/\*.*\*\///; }; "more appropriate, then delete empty lines on the line

• sed/^$/d filename Delete empty line, the actual application can change the-e parameter to-I, so that you can directly manipulate and modify the source file;

  Here's a script that removes the comments # of various C and C + + and shell scripts themselves
  #delete the comment line begin with '//comment '
  Sed-i "/^[\t]*\/\//d" $filename
  #delete the Commnet line end with '//comment '
  Sed-i "s/\/\/[^\"]*//"$filename
  #delete the comment only occupied a line '/* commnet */'
  Sed-i "s/\/\*.*\*\///" $filename
  #delete the comment that occupied many lines '/*comment
  # *comment
  #                                              */
  Sed-i "/^[\t]*\/\*/,/.*\*\//d" test.conf
  Sed-i ' s#\#.*# # ' $filename
  Sed-i ": Begin; { /\*\//! { $! {N; b begin}; }; s/\/\*.*\*\///;  };" $filename
  Sed-i '/^$/d ' $filename

Reproduced Shell deletes scripts for various annotations