Use a variable in a sed command

Question

I can\'t seem to use a variable in a sed command, for example:

sed \"24s/.*/\"$ct_tname\"/\" file1.sas > file2.sas

I want $ct_tnam

Answer 1

Other answers focus on the use of escaped double quotes in their examples. Note that this is not always what you want :

$ FOO="auie"; echo foo123bar|sed "s/123/\"$FOO\"/"
foo"auie"bar
$ FOO="auie"; echo foo123bar|sed "s/123/$FOO/"
fooauiebar
$ FOO="auie"; echo fooauiebar|sed "s/\"$FOO\"/123/"
fooauiebar
$ FOO="auie"; echo fooauiebar|sed "s/$FOO/123/"
foo123bar