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| Chapter 11 The Lessons of History |

## 11.10 Check Your History First with :p

Here's how to be more sure of your history before you use it. First, some review of csh and bash history substitutions:

- `!/` and `!fra` are replaced with the most recent command lines that started with `/` and `fra`, respectively.

- `!?af?` is replaced with the most recent command line that contained `af` anywhere on the line.

But if your memory is like mine (not very good), you might not be sure that `!?af?` will bring back the command you want. You can test it by adding `:p` to the end. The shell will print the substitution but won't execute the command line. If you like what you got, type `!!` to execute it. For example:

>     % !?af?:p
>     lp afile bfile cfile
>     % !!
>     lp afile bfile cfile
>     request id is 676

At the first prompt, the `:p` meant the command line was only printed. At the second prompt, I didn't use `:p` and the lp command was executed. The `:p` works with all history operators, not just with `!?...?`.

- JP

11.9 Running a Series of Commands on a File |  | 11.11 Picking Up Where You Left Off