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History Expansion
The shell offers a specialized type of expansion for items in the history list by using the “!” character. We have already seen how the exclamation point can be followed by a number to insert an entry from the history list. There are a number of other expansion fea- tures:
Table 8-6: History Expansion Commands
Sequence Action
Sequence Action
!! Repeat the last command. It is probably easier to press up arrow and enter.
!number Repeat history list item number.
!string Repeat last history list item starting with string.
!?string Repeat last history list item containing string.
I would caution against using the “!string” and “!?string” forms unless you are absolutely sure of the contents of the history list items.
There are many more elements available in the history expansion mechanism, but this subject is already too arcane and our heads may explode if we continue. The HISTORY EXPANSION section of the bash man page goes into all the gory details. Feel free to explore!
script
In addition to the command history feature in bash, most Linux distributions in- clude a program called script that can be used to record an entire shell session and store it in a file. The basic syntax of the command is:
script [file]
where file is the name of the file used for storing the recording. If no file is speci- fied, the file typescript is used. See the script man page for a complete list of the program’s options and features.