a friend just asked me about a shell script she's trying to write. she's got a file that looks like this:
blah blah thi. blah thi. blah blah blah thi. blah thi. blah blah blah
&c. -- lots of "thi."s in there.
she's trying something equivalent to:
word1=thi.; word2=this; sed 's/$word1/$word2/g' file > file.new;
and it doesn't replace.
variable substitution doesn't occur inside single quotes, use double quotes instead:
sed "s/$word1/$word2/g" file
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