Copying files
cp file1.txt{,.bak}
expands to:
cp file1.txt file1.txt.bak
Moving Files
mv /a/really/long/path/file{.txt,.html}
expands to:
mv /a/really/long/path/file.txt /a/really/long/path/file.html
cp file1.txt{,.bak}
expands to:
cp file1.txt file1.txt.bak
mv /a/really/long/path/file{.txt,.html}
expands to:
mv /a/really/long/path/file.txt /a/really/long/path/file.html