[TriLUG] history

[Aaron S. Joyner]

Phillip Rhodes wrote:

> Joseph Tate wrote:
>
>>
>> !100 will execute item 100 in your command history.  I generally do a 
>> history | grep something, and then !thenumber
>
>
> You can also do !string
> where string is the beginning of a previously
> entered command.  This will execute the last command
> starting with that string.
>
> Example:
>
> # ssh someuser at somehost.com
>
> later
>
> # !ssh
>
> will execute the most recent ssh command in history.
>
> TTYL,
>
> Phillip Rhodes
>

Along these same lines, lots of interesting variations are possible in 
bash, under "vi" mode.  Try: "set -o vi".  This allows you to, using the 
above ssh example, hit escape (to enter command mode, much like vi), 
then enter a regular expression of the form /ssh/ (the trailing slash is 
optional).  Press Enter and the command will be completed out to the 
last command which contained the regular expression specified.  For a 
more precise match /^ssh would probably be preferred.  Generally, if 
you're comfortable with vi and it's paradigm of command mode vs insert 
mode, this can be a very powerful and functional way to work at the 
command line.

Some might ask how this is different from the earlier history | grep 
example suggested - the basic answer, it all happens with in the shell 
process.  No external process overhead is required (so in some 
unmeasurable way it might be faster), but more importantly it's a 
"gateway" feature.  One of those things that once you start using it, 
you discover all of the other related things which make life that much 
more beautiful.  :)

Hope it helps!
Aaron J.