gsed replace by a variable $i with single quote

Question

I have into a text file the following line :

\[Omega]BD=100;

I would like to replace with gsed the value 100 by a shell variable (zsh shell), here 600 :

I tried :

$ i=600

$ gsed  's/\[Omega]BD=.*/\[Omega]BD=\'\\"$i"\\';/' text_to_modify.txt | grep 600

but it returns me :

\[Omega]BD=\600; and not \[Omega]BD=600;

The is an additional backslash that I don't want, I wonder how could I remove this backslash. I would like to keep the two single quotes of gsed 's/.../.../'

Answer 1

Using sed;

i=600
$ sed "/\[Omega]/s/[[:digit:]]\+/$i/" input_file
\[Omega]BD=600;