bash: Complex history command changes (history expansion).

[hoodedvul]

Take into account the main readme for this section. README first.

Note: Best not used on root type system work. More suited to development type work.

Also see: https://www.gnu.org/software/bash/manual/bash.html#History-Interaction

Changing a command using what is type so far. The !#:^.txt takes word 1, which is /home/training/abc and renames it with suffix .txt.

$ mv /home/training/abc !#:^.txt
mv /home/training/abc /home/training/abc.txt

Using a modifier to change the suffix.

$ mv /home/training/abc.txt !#:^:s/txt/pdf/
mv /home/training/abc.txt /home/training/abc.pdf