Commenting out lines in a file using a bash script.

[vamega]

Hi.

I was wondering if anyone could help me figure out how I could comment out certain lines in a file using a bash script.

The lines I'm looking for are


<IfModule mod_userdir.c>
<Directory /home/*/public_html>
php_admin_value engine Off
</Directory>
</IfModule>


I want to prefix every one of the above lines with a # so that the lines look like this.

# <IfModule mod_userdir.c>
# <Directory /home/*/public_html>
# php_admin_value engine Off
# </Directory>
# </IfModule>


Does anyone know how I could do this?

[Andrew_Grant]

Any plain text editor, vi, emacs for command line or gedit or kate for gnome or KDE, will do the job. Just remember to make sure you have permission. For example, sudo vi <path/file> or sudo gedit <path/file>. It is a good idea to save a copy of the file: cp <file> <file.copy> before attempting any editing.
Andrew

[vamega]

I know I could do this using any text editor.
But I was looking for a scripted way to do this.
What I need to do is identify the lines in the file, and then comment them out.

I originally thought of using sed, but I couldn't figure out how to get sed to do this.

[AdotB]

a simple way of using sed would be

sed "s/pattern/#pattern/" < $infile

heres a simple script using sed. the first argument is the input file name, all others are patterns to be commented.

#!/bin/bash
infile=$1
shift
while [ $# -gt 0 ]; do
pattern=$1
shift
sed "s/$pattern/#$pattern/" < $infile
done


Unfortunately, it doesn't place the # at the beginning of the line, but right before the pattern. But maybe its a start.

Awk might work better, but i've never used it.

[AdotB]

Heres a ruby script that comments lines by regular expression or line numbers.

#!/usr/bin/env ruby

def usage
puts <<EOS
Usage: #{__FILE__} [options] infile pattern1 [pattern2 ...]

-r --regexp comment all lines matchinp patterns (default)
-n --numbers comment by line numbers instead of patterns
-c --comment-mark <MARK> use <MARK> to comment (default=`#')
-f --file input file (default is first arg)
-h --help this help
EOS
end


$comment_mark = "#"
$by_number = false
$by_regexp = true
$input_file = nil

while ARGV.any?
case arg = ARGV.shift
when "-r", "--regexp"
$by_number = false
$by_regexp = true
when "-n", "--numbers"
$by_number = true
$by_regexp = false
when "-c", "--comment-mark", "--mark"
$comment_mark = ARGV.shift
when "-f", "--file"
$input_file = ARGV.shift
when "-h", "--help"
usage
exit 0
else
if $input_file
ARGV.unshift arg
else
$input_file = arg
end
break
end
end

unless $input_file
STDERR.write "no input file given\n"
exit 1
end

line_num = 0
File.open($input_file, 'r').each_line do |line|
line_num += 1
ARGV.each do |pattern|
if $by_number
number = pattern.to_i
if number == 0
STDERR.write "invalid line number: `#{pattern}'\n"
exit 1
end
if line_num == number
line = $comment_mark + line
end
elsif $by_regexp
if Regexp.new(pattern) =~ line
line = $comment_mark + line
end
end
end
puts line
end

[DaithiF]

using sed:

sed '/<IfModule mod_userdir.c>/,/<\/IfModule>/s/^/#/' somefile

add the -i flag to make the changes in-place to the file when you've confirmed the results are as you expected.

[vamega]

Thanks DaithiF.
That works beautifully.

[somekool]

great script, only missing an in-place option ...



Heres a ruby script that comments lines by regular expression or line numbers.

#!/usr/bin/env ruby

def usage
puts <<EOS
Usage: #{__FILE__} [options] infile pattern1 [pattern2 ...]

-r --regexp comment all lines matchinp patterns (default)
-n --numbers comment by line numbers instead of patterns
-c --comment-mark <MARK> use <MARK> to comment (default=`#')
-f --file input file (default is first arg)
-h --help this help
EOS
end


$comment_mark = "#"
$by_number = false
$by_regexp = true
$input_file = nil

while ARGV.any?
case arg = ARGV.shift
when "-r", "--regexp"
$by_number = false
$by_regexp = true
when "-n", "--numbers"
$by_number = true
$by_regexp = false
when "-c", "--comment-mark", "--mark"
$comment_mark = ARGV.shift
when "-f", "--file"
$input_file = ARGV.shift
when "-h", "--help"
usage
exit 0
else
if $input_file
ARGV.unshift arg
else
$input_file = arg
end
break
end
end

unless $input_file
STDERR.write "no input file given\n"
exit 1
end

line_num = 0
File.open($input_file, 'r').each_line do |line|
line_num += 1
ARGV.each do |pattern|
if $by_number
number = pattern.to_i
if number == 0
STDERR.write "invalid line number: `#{pattern}'\n"
exit 1
end
if line_num == number
line = $comment_mark + line
end
elsif $by_regexp
if Regexp.new(pattern) =~ line
line = $comment_mark + line
end
end
end
puts line
end

[sisco311]

RIP, old thread.

http://ompldr.org/tYnpyNw (http://ompldr.org/vYnpyNw)