To run the most recent command that begins with a given string, use an exclamation mark followed by that string. For example, to run the last command that started with a D, type exclamation mark D enter. Specify as much of the string as required to make it unique. If you have several commands in your recent history that began with the letter D you can add additional characters, like exclamation mark D U or exclamation mark D F.

I find myself using this technique to get a status, perform some work that might affect that status. and then to recheck that status again. Here's an example where data is being copied to a file system that where the disc usage is being checked. Let's change into a directory of our plan to restore some data. I'll check the disc usage with a df command and now I will extract some data into this directory. And then using exclamation mark D, I will recheck the status. You can see that about 400 megabytes of data was extracted into this file system.

Here's an example that demonstrates a situation where more than just one character of a string is required to recall the desired command. Let's create a directory for my fictitious application called myapp. Let's create a user for this application. And we'll make that application owner the owner of the directory here. And if I run an exclamation mark M, the most recent command that begins with M is mkdir. So it will run mkdir myapp.

Now, if I want to run C H O W N to change the ownership I will have to specify C H O if I just specify C, cd will execute. I specify C H, chmod will execute. So to run chown I need to specify exclamation mark C H O and then if I want to run the chmod command I will specify just enough as required to make that unique. I could specify more if I wanted, for instance.