History and using old commands

Creating, viewing, and using history

• Typing 'set history=20' (or some other number) or having it in your .dot files will allow you to use previous commands
• For example, suppose $history = 4, and I type 'history' at the prompt. then I will see something like

        33    ls

        34        cc test.c >  test.out

        35        vi test.c

        36        history

• Once I have a history (whether or not i display it), I can re-execute commands using a ! special character

        !!        re-executes the last command

        !33       would re-execute command 33

        !cc       would re-execute the last command starting with 'cc'

• (in either of the last two cases, get a 'not found' error if there is no such command in the history)

        !33       -lga

• will execute 'ls -lga'

        !34 || !35     (tell me)

        !34 & &  !33     (tell me)

• I don't think !33t would invoke a command 'lst' (if there were one) but you could check.