Ran into this issue at a client site today so I thought I would post some info on it. I see a lot of Windows administrators that don’t know how to fully leverage the Windows auto-complete functionality as well as the command line history. I also see Linux and UNIX administrators who get confused because these features work differently under Windows. Thought I would write up a quick how-to.
Windows auto-complete
Auto-complete permits you to type in a portion of a file name and have the system fill in the rest of the name for you. It’s a great way to save a few keystrokes. Simply type in the first couple of letters for the file name and press the <tab> key. The first file in the current directory, which starts with the letters you typed, will be filled in on the command line. This is shown in Figure #1.
For the folks that have used auto-complete on UNIX or Linux, here is where they get confused. Both platforms require you to type in enough of the command to be unique. You can then press <tab> to fill in the rest of the file. Windows works a little different.
Note in Figure #1 Windows filled in the first file name match to the character string “nets” the first time the <tab> key was pressed. If this is not the file you wanted, simply press the <tab> key a second time. You can continue to press the <tab> key and scroll through all of the possible file options.
Eventually the system will wrap and return to the first file it presented. For example pressing <tab> six times in the above example will return you to the file named “netsetup.cpl”. If you need to scroll backwards through the file options, simply hold down the <shift> key while you press <tab>.
Windows command history
Most folks realize you can press the up and down arrow keys to scroll through your command line history. Have you tried the <F7> key? If you are working in a command prompt and press the function 7 key ( <F7> ), a menu appears showing all the commands that you typed. This is shown in Figure #2. You can then use the up and down arrows, as well as the <Page Up> and <Page Down> keys, to navigate this list of commands.
Here’s another area where Windows works a little differently than Linux and UNIX. With Linux and UNIX, pressing the up arrow will always retrieve the last command you typed. If you have 10 sequential commands you wish to repeat, you will have to repeatedly hit the up arrow key 10 times to retrieve each command in sequence. Windows makes this process a little easier.
Try this on your Windows system:
- Open a command prompt
- Type the number 1 and press <enter>
- Ignore the command not found error
- Repeat the last two steps for numbers 2 – 10
- Press the up arrow till you retrieve the number 5
- Press enter
- Press <F7>
An example is shown in Figure #3. Note the menu bar is over the number 5. This is the current reference point in the command history. While pressing the up arrow on a Linux or UNIX command line will always recalls the last command you typed, Windows shift the reference point to last recalled command. So pressing up arrow recalls the command prior to the last recalled command, not the last executed command like Linux and UNIX.
To test this, press the <Esc> key. This will return you to the command prompt. Now press the up arrow. This will recall “4”, the command prior to “5” in the history, not “10” which was the last command executed prior to recalling “5”. Now press the down arrow until the “7” command is displayed and press <Enter>. If you now press <F7> you will notice the reference pointer has been moved to “7”, the last recalled command.
Exec Summary
Some functions operated differently at the Windows command line than their UNIX or Linux counterparts. Auto-complete and command line history are two great examples. Which implementation is preferable, unusually depends on which operating system you are most comfortable using.
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