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How to prepend/(insert a string) in a file at arbitrary line numbers to multiple files in a directory?

开发者 https://www.devze.com 2023-01-02 01:16 出处:网络
Appending can be done using tee command. cat file | tee -开发者_如何学Ca >> * Is there a way to do a prepend/insertion?

Appending can be done using tee command.

cat file | tee -开发者_如何学Ca >> *

Is there a way to do a prepend/insertion? Thanks.


Using sed might help

example:

sed -i.bak '3 r tmp1.txt' settings.xml 

will add the contents of tmp1.txt after line 3 in settings.xml (and create a backup file with the .bak extension)


Just a brief example: say, comment out specific/particular/arbitrary C lines:

$ echo -e "1\n2\n3\n4\n5\n6\n" | sed "3s,^,/* ,;5s,$, */,"
1
2
/* 3
4
5 */
6

Note:

  • single sed command follows a format "${linenum}s/${search}/${replace}/"
  • then two commands can be delimited by a semicolon ';'
  • using a comma ',' as delimiter, for easier reading of s///
  • Caret '^' matches start of line; dollar '$' matches end of line; the s/// will replace only those (meta?)"characters"

Of course, then this should be modified with the -i switch to sed, to eventually replace file contents..

Cheers!

EDIT: Refs:

  • Can we give multiple patterns to a sed command??? - The UNIX and Linux Forums
  • Cute ‘sed’ Tricks to Modify Specific Lines Within File | The Linux Daily
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