How to insert character before match pattern using vim or sed?

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int main () {
  int a = 1;
}

change to

#int main() {
  #int a = 1;
#}

How to insert '#' before each line?


Linux: Using sed to insert lines before or after a match – Fabian Lee , Linux: Using sed to insert lines before or after a match /11694980/using-sed-​insert-a-line-below-or-above-the-pattern (insert below match). sed: Insert character in the beginning or end of line with matched pattern. In my last articles I had shared the arguments with sed which can be used to perform case insensitive actions (search, replace..) in a file and to delete all blank lines from the file.


This should do it for you:

:%s/\(^.*$\)/#\1/g

Insert newline before each line matching a pattern unless the , You could store the previous line in the hold space: sed ' /^pattern/{ x /./ { x s/^/\ / x } x } h'. It would be more legible with awk though: (with no arguments) will insert a newline before each of the search hits, and using :%LineBreakAt will insert a newline after each of the search hits. Explanation Edit. The :command line defines a user command (LineBreakAt) that calls a function with the same name.


My attempt:

:%norm! _i#

% ......... hole file
nomrm! .... normal mode
_ ......... first non-blank of the line
i# ........ insert comment

Vim Regular Expressions 101, For each line in the range replace a match of the pattern with the string where: Before I begin with a pattern description let's talk about line addresses in Vim. and that will search for the next Section line and put (paste) the saved text on the Obviously, it is not very convenient to write \w for any character in the pattern  Linux: Using sed to insert lines before or after a match The sed utility is a powerful utility for doing text transformations. In this article, I will provide an example of how to insert a line before and after a match using sed, which is a common task for customizing configuration files.


A possible vim approach using block edit

ggctrl-vGI#esc

Start with gg followed by ctrl + v , then GI. Now press the character you want to insert, # and finalize it with esc

Unix Sed Tutorial: Append, Insert, Replace, and Count File Lines, The below sed command will add a line “Linux Scripting” before every line that matches with the pattern called 'Sysadmin”. $ sed '/Sysadmin/i  The Power of sed. The sed command is a bit like chess: it takes an hour to learn the basics and a lifetime to master them (or, at least a lot of practice). We’ll show you a selection of opening gambits in each of the main categories of sed functionality.


In vim: First make sure you are not in insert mode by hitting the escape key. Then hit the colon key and enter:

1,3s/^[ \t]*/&#/

This says from lines 1 through 3, after the beginning of the line and some possible spaces and/or tabs, repeat those possible spaces and/or tabs and append a hash symbol.

Vim inserting characters before a comma on multiple lines, I'm guessing that I can use visual block mode? I realize I could easily do this with sed, but I'm interested in any way that I could do this WITHOUT leaving vim. In my last articles I had shown you the arguments to be used with sed to add or append any character in the beginning or end of the line and to ignore whitespace while grepping for a pattern so that the grep does not fails if there is an extra whitespace character between two words or sentence.


Search and replace | Vim Tips Wiki, Vim provides the:s (substitute) command for search and replace; this tip shows with [^ instead of [ ; for example [^1a-c] matches any character except a, b, c, or 1. After pressing Ctrl-R then / to insert the last search pattern (and before  I need to add a new line before any line containing a pattern where we can assume that the pattern is always the first string of the current line. For example. This is a pattern This is a pattern I can add a new line with the sed command. sed -i 's/pattern\+/ &/g' file to get the output. This is a pattern This is a pattern


Add a newline after given patterns | Vim Tips Wiki, You may need to insert a line break (newline) before or after each occurrence of In the substitute command, the find pattern is empty, so the last search is used; Similarly, we don't want to break on a comma but on the next non-space character. e flag prevents an error message being displayed if no matches are found. In this article, we will see the different ways in which we can insert a line before or after on finding a pattern. On finding the pattern 'Fedora', the requirement is to insert a line: The '1' at the end prints every line by default. On finding the pattern 'Fedora', 'Cygwin' is printed. Hence, first "Cygwin" gets printed followed by 'Fedora' (1).


Vim tips: The basics of search and replace, Without adding g, your search will match only the first instance of a You may also wish to be asked for confirmation before Vim makes a substitution. Searches in Vim put the cursor on the first character of the matched  With awk:. awk '1;/PATTERN/{ print "add one line"; print "\\and one more"}' infile Keep in mind that some characters can not be included literally so one has to use escape sequences (they begin with a backslash) e.g. to print a literal backslash one has to write \\.