Add line to configuration file from a bash script?

Question

I am trying to figure out to locate a line in a configuration file, then to drop down two lines then to insert a line of code. I was attempting to do this in awk/sed but got stuck on the carriage return. I not tied to awk/sed but looking for a clean way to accomplish this.

<Location />
  Order allow,deny
</Location>

Then to add a line into that block:

<Location />
  Order allow,deny
  Allow all
</Location>

Answer 1

sed '/Order allow,deny/ aAllow all' < yourFile

This will output the modified file to stdout. If you want to modify it in place then (sed(1)):

-i[SUFFIX], --in-place[=SUFFIX]

          edit files in place (makes backup if SUFFIX supplied)

Explanation:

For each line that matches `/Order allow,deny/`:
     Execute command 'a' (append) with 'Allow all' as parameter

http://grymoire.com/Unix/sed.html is an excellent resource to learn more about sed.

Answer 2

awk can be used for this. The bellow script will only add text after finding a <Location /> tag.

awk '/\<Location \/\>/{ start=1 } {if(start) ++start; if(start==4) print "  Allow all"} 1' infile

For the the bellow input file:

stuff
<Location />
  Order allow,deny
</Location>
more
stuff

This script produces:

stuff
<Location />
  Order allow,deny
  Allow all
</Location>
more
stuff

If you want to replace several sections like this, the same script can be easily adapted:

awk '/\<Location \/\>/{ start=1 } {if(start) ++start; if(start==4){print "  Allow all"; start=0}} 1' infile

Answer 3

If you just blindly want to add the Allow all statement after any Order allow,deny then the following sed will work

sed -i 's/Order\ allow,deny/Order\ allow,deny\nAllow\ all/' <inputfilename>

Answer 4

You can use Vim in Ex mode:

ex -sc '/Order allow,deny/a|Allow all' -cx file

1. a append text and newline

2. x save and close