Often, I use parameter expansion on the command-line, such as
which is expands to
cp a.ext1 a.ext2
However, in many cases I do not use
cp, but another tool, let's call it
cat, and I would do some output redirection, like
cat a.ext1 > a.ext2
In my case
a can vary, or be quite long, so I would like to be able to use some sort of brace expansion, that at least needs only one occurrence of
a in the one-liner. How can I obtain that?
I am specifically using
$ bash --version GNU bash, version 3.2.51(1)
but answers using other shells are also appreciated.