expand unix variable inside sed command [duplicate]

Question

I need to replace current value in configuration file with new value which is assigned to variable ,

like

file_name=abc.txt

needs to be replaced like

file_name=xyz.txt

where $file=xyz.txt

I tried

sed -i 's/file_name=.*/file_name=$file/g'  conf_file.conf

however the variable is not getting expanded, it comes like file_name=$file.

any pointers?

i tried with above duplicate thread but in my case it shoudl search for 'file_name= ' and then replace with 'file_name=xyz.txt' — katty
– katty, Commented Sep 28, 2018 at 8:33
The duplicates say to use double quotes not single quotes. If you tried that it would work. — Jonathan Wakely
– Jonathan Wakely, Commented Sep 28, 2018 at 9:28

ashish_k · Accepted Answer · 2018-09-28 09:41:19Z

3

This should work,assuming that variable file has value:xyz.txt assigned to it:

sed "s/file_name=.*/file_name=${file}/g" file_name

Output:

file_name=xyz.txt

edited Sep 28, 2018 at 9:41

answered Sep 28, 2018 at 8:55

ashish_k

1,5912 gold badges14 silver badges28 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

Jonathan Wakely Over a year ago

But this will not work if $file has spaces in it. Why have you used ${file} outside the double quotes? That's not necessary, and makes it wrong if the variable contains whitespace.

ashish_k Over a year ago

That's right..Thanks @JonathanWakely for the suggestion..i think it should work with my edited answer.I've removed double quotes " " from the ${file}

katty Over a year ago

its not working tried with ......... sed "s/$$file_name=.*/$$file_name=${file}/g" file_name

Jonathan Wakely Over a year ago

Why have you added $$? That will give you the process ID of your current shell, which is not what you want. Why don't you try what people have actually suggested, instead of trying something else that doesn't work?

katty Over a year ago

actually in my config file the file_name will be as $$file_name, so tried with that, its informatica config file, where parameters will be given by $$parameter_name

|

Collectives™ on Stack Overflow

expand unix variable inside sed command [duplicate]

1 Answer 1

6 Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

6 Comments

Linked

Related