BASH - Add lines to file after text is found

[zerowizard]

Basically, I just need to search a text file for a line, then add a couple lines, with user input, to the file. (Radius server user file)
I've tried using sed, but continue to run into problems.

I am using something similar to the code below.
It is not working at all. I'm new to sed.

read variable
STRING=$variable "Auth-Type := Local, User-Password == "$variable"
 Service-Type = Login-User"

sed -i 's/SearchTerm/'$STRING'/g' userfile

As you can see, the string that needs to replace the line, not only has a break in it, but it also contains the entered variable.

Any help is greatly appreciated.

[histrungalot]

I have looked for this before and still can't seem to find the answer for sed. That said, I did find this:

#!/bin/bash
read input
{ rm userfile; awk '{ if ( $0 ~ /SearchTerm/ ) {
         printf("Auth-Type := Local, User-Password == %s\nService-Type = Login-User\n","'$input'");
     } else {
         print $0;
     }
}' > userfile; } < userfile

Before

$ cat userfile
This
SearchTerm
is
a 
test

After

$ ./theScript
MyLogInInfo
$ cat userfile
This
Auth-Type := Local, User-Password == MyLogInInfo
Service-Type = Login-User
is
a 
test
$

Used this as a reference: sed.. Add new line after finding text - The UNIX and Linux Forums

[atreyu]

the above solution works good. for a sed solution, you can use the newline character (\n) instead of actual new lines, e.g.:

STRING="$variable \"Auth-Type := Local, User-Password == \"$variable\"\n Service-Type = Login-User"
sed -i "s/SearchTerm/$STRING/" userfile

also, note that:
1. double-quotes in the variable have to be escaped
2. the entire variable needs to be enclosed in double-quotes
3. the sed line needs double-quotes around the entire expression, and the single-quotes around the variable name are not needed.

[alf55]

I am assuming that you do not wish to remove the "search string" line.

This will take the userfile of:

This
SearchTerm
is
a 
test

and an entered string of

VARIBALE VAUE FROM READ INPUT

Using the code:

read variable
mv userfile userfile.old
sed -f <(echo $"/SearchTerm/ a\
$variable \"Auth-Type := Local, User-Password == \"$variable\" \
 Service-Type = Login-User/") < userfile.old >userfile
rm userfile.old

and will result in userfile of:

This
SearchTerm
VARIBALE VAUE FROM READ INPUT "Auth-Type := Local, User-Password == "VARIBALE VAUE FROM READ INPUT"  Service-Type = Login-User/
is
a 
test

One should not edit a file in place with sed.

[histrungalot]

alf55: Gives an error?

./bb
MyLogin 
sed: 1: /dev/fd/63: command a expects \ followed by text

atreyu: Gives an error?

./bb
MyTest
sed: 1: "i\n": command i expects \ followed by text

I am using a Mac, if that makes a difference?

[zerowizard]

I found an easy solution using awk:

#!/bin/bash
var1="New line 1"
var2="New line 2"
search="Search term"
awk -v S="$search" -v V1="$var1" -v V2="$var2" '{if ($0~S) print $0 "\n" V1 "\n" V2; else print $0}' users > users.tmp
mv users.tmp users

[atreyu]

atreyu: Gives an error?

./bb
MyTest
sed: 1: "i\n": command i expects \ followed by text

oh, my bad. i just copied that part of the code from the OP, then modified the regex parts. i didn't notice that the -i was not followed by the required argument, that is, a file extension. you could try sed -i.bak ... , which would make a back up of the file first (named "original_filename.bak"), and the changes would be made inline to the existing file. Or you could leave off -i altogether and not make the backup copy.