Bash - Search and append strings

Question

If I wanted to search for a line in a file and append a string to the end of that line, how can I go about it? IE:

file=?

I want to search for file=? and replace the question mark with a file path. The file path is located in a variable $FILEPATH

file=$FILEPATH

Thanks!

EDIT

sed -i -f "s,file=\?,file=$FILEPATH,g"

The above works well and is what I'm looking for but is there a way to replace the question mark? With the code above if I have the following:

FILEPATH=/file/path

Properties file:

something=?
file=?

The replacement produces:

Properties file:

something=?
file=/file/path?

Is there a way to replace the ? completely?

Answer 1

I'd use sed for that:

sed -i "s/file=?/file=$FILEPATH/g" your_file

If your $FILEPATH has / then use a different sed separator, something like:

sed -i "s,file=?,file=$FILEPATH,g"

Answer 2

Don't escape your question mark

[jaypal:~/Temp] cat temp
file=?
file=?

[jaypal:~/Temp] echo $filepath
/usr/bin

[jaypal:~/Temp] sed -e 's_file=?_file='$filepath'_g' temp
file=/usr/bin
file=/usr/bin

Also to make inline changes I would recommend to use the following -

[jaypal:~/Temp] sed -ibak 's_file=?_file='$filepath'_g' temp

[jaypal:~/Temp] ls temp*
temp    tempbak

[jaypal:~/Temp] cat temp
file=/usr/bin
file=/usr/bin

[jaypal:~/Temp] cat tempbak
file=?
file=?

This will make a backup copy of your original file before making any changes. In case if anything goes wrong you will have your original copy protected.

Answer 3

If you are using Bash, you can simply use Bash builtins and substitutions instead of sed:

#!/bin/bash

FILEPATH="/file/path"

while read line; do
    echo "${line/file=\?/${line/\?/}$FILEPATH}"
done < yourfile