Personalizing the User Environment in BSD

In this second part of a three-part article, you’ll learn a few more ways to personalize the user environment in BSD, such as adding some fun trivia, setting up a trash directory, and locking down your screen. It is excerpted from chapter one of the book BSD Hacks, written by Dru Lavigne (Copyright © 2005 O’Reilly Media, Inc. All rights reserved. Used with permission from the publisher. Available from booksellers or direct from O’Reilly Media; ISBN: 0596006799).

Hack 5: Use the Mouse at a Terminal

Use your mouse to copy and paste at a terminal.

If you’re used to a GUI environment, you might feel a bit out of your element while working at the terminal. Sure, you can learn to map hotkeys and to use navigational tricks, but darn it all, sometimes it’s just nice to be able to copy and paste!

Don’t fret; your mouse doesn’t have to go to waste. In fact, depending upon how you have configured your system, the mouse daemon moused may already be enabled. The job of this daemon is to listen for mouse data in order to pass it to your console driver.

Of course, if you’re using screen [Hack #12], you can also take advantage of its copy and paste mechanism.

If X Is Already Installed

If you installed and configured X when you installed your system, moused is most likely started for you when you boot up. You can check with this:

  % grep moused /etc/rc.conf 
  moused_port="/dev/psm0" 
  moused_type="auto"
  moused_enable="YES"

Very good. moused needs to know three things:

  • The mouse port (in this example, /dev/psm0, the PS/2 port)
  • The type of protocol (in this example, auto )
  • Whether to start at boot time

If you receive similar output, you’re ready to copy and paste.

To copy text, simply select it by clicking the left mouse button and drag ging. Then, place the mouse where you’d like to paste the text and click the middle button. That’s it.

To select an entire word, double-click anywhere on that word. To select an entire line, triple-click anywhere on that line.

Configuring a two-button mouse. What if you don’t have three mouse buttons? As the superuser, add the following line to /etc/rc.conf (assuming it’s not already there):

  moused_flags="-m 2=3"

This flag tells moused to treat the second, or right, mouse button as if it were the third, or middle, mouse button. Now you can use the right mouse button to paste your copied text.

To apply that change, restart moused :

  # /etc/rc.d/moused restart
  Stopping moused.
  Starting moused:.

{mospagebreak title=Hack 6: Get Your Daily Dose of Trivia}

Test your change by copying some text with the left mouse button and past ing with the right mouse button.

If X Is Not Installed

You can achieve the same results on a system without X installed. You’ll have to add the lines to /etc/rc.conf manually, though.

The example I’ve given you is for a PS/2 mouse. If you’re using another type of mouse, read the “Configuring Mouse Daemon” section of man moused . It gives explicit details on figuring out what type of mouse you have and what type of protocol it understands. It even includes a section on configuring a laptop system for multiple mice: one for when on the road and one for when the laptop is attached to the docking station.

For example, if you’re using a USB mouse, the only difference is that the port is /dev/usm0 instead of /dev/psm0 .

A serial mouse physically plugged into COM1 would be /dev/cuaa0 . You may have to experiment with the type, as auto doesn’t work with all serial mice. Again, the manpage is your best reference.

See Also

  • man moused
  • Documentation on enabling mouse support in NetBSD at http://www.netbsd.org/Documentation/ wscons/
  • Documentation on enabling mouse support in OpenBSD at http://www.openbsd.org/faq/faq7.html)

Brighten your day with some terminal eye candy.

 

As the saying goes, all work and no play makes Jack a dull boy. But what’s a poor Jack or Jill to do if your days include spending inordinate amounts of time in front of a computer screen? Well, you could head over to http://www.thinkgeek.net/  to stock up on cube goodies and caffeine. Or, you could take advantage of some of the entertainments built into your operating system.

A Fortune a Day

Let’s start by configuring some terminal eye candy. Does your system quote you a cheery, witty, or downright strange bit of wisdom every time you log into your terminal? If so, you’re receiving a fortune:

  login: dru
  Password:
  Last login: Thu Nov 27 10:10:16 on ttyv7
  "You can’t have everything. Where would you put it?"
                        — Steven Wright

If you’re not receiving a fortune, as the superuser type /stand/sysinstall . Choose Configure , then Distributions , and select games with your spacebar. Press Tab to select OK , then exit out of sysinstall when it is finished.

Then, look for the line that runs /usr/games/fortune in your ~/.cshrc file:

  % grep fortune ~/.cshrc
  /usr/games/fortune

If for some reason it isn’t there, add it:

  % echo ‘/usr/games/fortune’ >> ~/.cshrc

Don’t forget to use both greater-than signs; you don’t want to erase the contents of your .cshrc file! To test your change, use the source shell command, which re-executes the contents of the file. This can come in handy if you’ve updated an alias and want to take advantage of it immediately:

  % source ~/.cshrc
  Indifference will be the downfall of mankind, but who cares?

If you’d also like to receive a fortune when you log out of your terminal, add this line to the end of your .logout file. If you don’t have one, and there isn’t one by default, you can create it and add this line in one step:

  % echo ‘/usr/games/fortune’ > ~/.logout

Note that this time I used only one greater-than sign, as I was creating the file from scratch. If the file already exists, use two greater-than signs to append your new line to the end of the existing file.

Believe it or not, fortune comes with switches, some of which are more amusing than others. I’ll leave it to you to peruse man fortune .

Pursuing Trivia

I’m a trivia buff, so I love using the calendar command. Contrary to logic, typing calendar won’t show me this month’s calendar (that’s the job of cal ). However, I will get an instant dose of trivia, related to the current date:

  % calendar
 
Nov 27     Alfred Nobel establishes Nobel Prize, 1895
  Nov 27     Friction match invented, England, 1826
  Nov 27     Hoosac Railroad Tunnel completed, 1873, in NW Massachusetts
  Nov 28     Independence Day in Albania and Mauritania
  Nov 28     Independence from Spain in Panama
  Nov 28     Proclamation of the Republic in Chad
  Nov 27     Jimi Hendrix (Johnny Allen Hendrix) is born in Seattle, 1942

Cool. I had forgotten it was the anniversary of the Hoosac tunnel, an event that put my hometown on the map.

It’s an easy matter to automate the output provided by calendar . If you want to see your trivia when you log in or log out, simply add a line to your .cshrc or .logout file. Because the line you add is really just a path to the program, use the output of the which command to add that line for you:

  % echo `which calendar` >> .cshrc

Again, don’t forget to append with >>, or have noclobber set in your .cshrc file [Hack #2].

Sundry Amusements

Of course, there are several other date and time related mini-hacks at your disposal. Here are two you might enjoy.

The current time. Ever wonder what time it is while you’re working on the terminal? Sure, you could use date , but the output is so small and boring. Try this the next time you want to know what time it is:

  % grdc

Whoa, you can see that one from across the room. That’s not a bad idea if you want to send your cubicle buddy a hint.

I’ve been known to add /usr/games/grdc to my ~/.logout. When I log out, my terminal displays the time until I press Ctrl-c and log in again. That’s sort of a built-in password protected screen saver for the terminal.

The phase of the moon. Have you ever read man pom ? It has one of the more useful descriptions I’ve seen:

The pom utility displays the current phase of the moon. Useful for selecting software completion target dates and predicting managerial behavior.

Sounds like Dilbert had a hand in that one. If I add the line /usr/games/pom to my ~/.cshrc, I’ll learn a bit about astronomy when I log in:

  % pom
  The Moon is Waxing Gibbous (53% of Full)

There’s a one-liner to promote water cooler conversation.

Adding Some Color to Your Terminal

Have you ever tried this command?

  % vidcontrol show 
  
0            8 grey
  1 blue       9 lightblue
  2 green     10 lightgreen
  3 cyan      11 lightcyan
  4 red       12 lightred
  5 magenta   13 lightmagenta
  6 brown     14 yellow
  7 white     15 lightwhite

Gee, that reminds me of my old DOS days when I discovered ansi.sys. Yes, your terminal is capable of color and you’re looking at your possible color schemes! (It likely looks much more exciting on your terminal, since it’s not in color in this book.)

If you see some colors that appeal to you, add them to your terminal. For example, this command will set the foreground color to yellow and the background color as blue:

  % vidcontrol yellow blue

Note that you can use only colors 1 through 7 as background colors; you’ll receive a syntax error if you try to use colors 8–15 in your background. Try out the various combinations until you find one that appeals to your sense of taste. You can even add a border if you like:

  % vidcontrol -b red

These settings affect only your own terminal. If you want, add the desired vidcontrol lines to your ~/.cshrc file so your settings are available when you log into your terminal.

If you have problems finding your cursor, try:

  % vidcontrol -c blink

or:

  % vidcontrol -c destructive

Changing the cursor affects all virtual terminals on the system. If other users complain about your improvement, this will bring things back to normal:

  % vidcontrol -c normal

See Also

  • man fortune
  • man calendar
  • man vidcontrol 
  • The games packages, in NetBSD and OpenBSD

{mospagebreak title=Hack 7: Lock the Screen}

Secure your unattended terminal from prying eyes.

If you work in a networked environment, the importance of locking your screen before leaving your workstation has probably been stressed to you. After all, your brilliant password becomes moot if anyone can walk up to your logged in station and start poking about the contents of your home directory.

If you use a GUI on your workstation, your Window Manager probably includes a locking feature. However, if you use a terminal, you may not be aware of the mechanisms available for locking your terminal.

As an administrator, you may want to automate these mechanisms as part of your security policy. Fortunately, FreeBSD’s screen locking mechanism is customizable.

Using lock

FreeBSD comes with lock (and it’s available for NetBSD and OpenBSD). Its default invocation is simple:

  % lock
  Key: 1234
  Again: 1234
  lock /dev/ttyv6 on genisis. timeout in 15 minutes.
  time now is Fri Jan 2 12:45:02 EST 2004 
  Key:

Without any switches, lock will request that the user input a key which will be used to unlock the terminal. This is a good thing, as it gives the user an opportunity to use something other than her login password. If the user tries to be smart and presses Enter (for an empty password), the lock program will abort.

Once a key is set, it is required to unlock the screen. If a user instead types Ctrl-c, she won’t terminate the program. Instead, she’ll receive this message:

  Key: lock: type in the unlock key. timeout in 10:59 minutes

Did you notice that timeout value of 15 minutes? At that time, the screen will unlock itself, which sorta diminishes the usefulness of locking your screen. After all, if you run into your boss in the hall, your 5-minute coffee break might turn into a 25-minute impromptu brainstorming session.

To lock the terminal forever, or at least until someone types the correct key, use the -n switch. If the system is a personal workstation, -v is also handy; this locks all of the virtual terminals on the system, meaning a passerby can’t use Alt-Fn to switch to another terminal.

As an administrator, you can assist users in using the desired switches by adding an alias to /usr/share/skel/dot.cshrc [Hack #9]. This alias removes the timeout and locks all terminals:

  alias lock  /usr/bin/lock -nv

Using autologout

If you use the tcsh shell, you also have the ability either to lock your session or to be logged out of your session automatically after a set period of inactiv ity. As an administrator, you can set your policy by adding a line to /usr/ share/skel/dot.cshrc.

Do be aware, though, that a user can edit her own ~/.cshrc file, which will negate your customized setting.

The autologout variable can accept two numbers. The first number represents the number of minutes of inactivity before logging out the user. The second number represents the number of minutes of inactivity before locking the user’s screen. Once the screen is locked, the user must input the password to unlock it. If the screen is not unlocked in time, the user will be logged out once the shell has been idle for the logout period of minutes.

The manpage is pretty vague on how to set those two numbers. For example, if you try:

  set autologout = 30 15

users will receive this error message when they try to log in:

  set: Variable name must begin with a letter.

That’s a deceptive error message, as this variable does accept numerals. The correct invocation is to enclose the two numbers between parentheses:

  set autologout = (30 15)

This particular setting will log out a user after 15 minutes of inactivity. The user will know this happened as the terminal will resemble:

  %
  Password:

After 30 minutes of inactivity (or 15 minutes after the screen was locked), the user will be logged out and see this:

  %
  Password:auto-logout

Consider whether or not your users tend to run background jobs before globally implementing autologout. Also see "Use an Interactive Shell” [Hack #11], which allows users to reattach to their terminals.

Enforcing Logout

What if you do want to enforce a logout policy that users can’t change in their shell configuration files? Consider using idled , which can be installed from /usr/ports/sysutils/idled or built from source. This utility was designed to log out users either after a configured period of inactivity or after they’ve been logged in for a certain amount of time.

Once you’ve installed idled , copy the template configuration file:

# cd /usr/local/etc/
# cp idled.cf.template idled.cf

Open /usr/local/etc/idled.cf using your favorite editor. You’ll find this file to be well commented and quite straightforward. You’ll be able to configure the time before logout as well as when the user will receive a warning message. In addition, you can refuse logins, set session timeouts, and provide for exemptions.

See Also

  • man lock
  • man tcsh man idled
  • man idled.cf 
  • The idled web site (http://www.darkwing.com/idled/)

{mospagebreak title=Hack 8: Create a Trash Directory}

Save “deleted” files until you’re really ready to send them to the bit bucket.

One of the first things Unix users learn is that deleted files are really, really gone. This is especially true at the command line where there isn’t any Windows-style recycling bin to rummage through should you have a change of heart regarding the fate of a removed file. It’s off to the backups! (You do have backups, don’t you?)

Fortunately, it is very simple to hack a small script that will send removed files to a custom trash directory. If you’ve never written a script before, this is an excellent exercise in how easy and useful scripting can be.

Shell Scripting for the Impatient

Since a script is an executable file, you should place your scripts in a directory that is in your path. Remember, your path is just a list of directories where the shell will look for commands if you don’t give them full path-names. To see your path:

  % echo $PATH    
  PATH=
/sbin:/bin:/usr/sbin:/usr/bin:/usr/games:/ usr/local/sbin:/usr/ 
  local/bin:/usr/X11R6/bin:/home/dru/bin

In this output, the shell will look for executables in the bin subdirectory of dru ’s home directory. However, it won’t look for executables placed directly in my home directory, or /home/dru. Since bin isn’t created by default, I should do that first:

  % cd
  %
mkdir bin

As I create scripts, I’ll store them in /home/dru/bin, since I don’t have permission to store them anywhere else. Fortunately, no one else has permission to store them in my bin directory, so it’s a good match.

The scripts themselves contain at least three lines:

  #!/bin/s h
  # a comment explaining what the script does
  the command to be executed

The first line indicates the type of script by specifying the program to use to execute the script. I’ve chosen to use a Bourne script because that shell is available on all Unix systems.

Your script should also have comments, which start with the # character. It’s surprising how forgetful you can be six months down the road, especially if you create a lot of scripts. For this reason, you should also give the script a name that reminds you of what it does.

The third and subsequent lines contain the meat of the script: the actual command(s) to execute. This can range from a simple one-liner to a more complex set of commands, variables, and conditions. Fortunately, we can make a trash script in a simple one-liner.

The Code

Let’s start with this variant, which I found as the result of a Google search:

  % more ~/bin/trash
  #!/bin/sh
  # script to send removed files to trash directory
  mv $1 ~/.trash/

You should recognize the path to the Bourne shell, the comment, and the mv command. Let’s take a look at that $1 . This is known as a positional parame ter and specifically refers to the first parameter of the trash command. Since the mv commands takes filenames as parameters, the command:

  mv $1 ~/.trash/

is really saying, mv the first filename, whatever it happens to be, to a directory called .trash in the user’s home directory (represented by the shell shortcut of ~ ). This move operation is our custom “recycle.”

Before this script can do anything, it must be set as executable:

  % chmod +x ~/bin/trash

And I must create that trash directory for it to use:

  % mkdir ~/.trash

Note that I’ve chosen to create a hidden trash directory; any file or directory that begins with the . character is hidden from normal listings. This really only reduces clutter, though, as you can see these files by passing the -a switch to ls . If you also include the F switch, directory names will end with a /:

  % ls -aF ~
  .cshrc     .history   .trash/
  bin/       images/    myfile

Replacing rm with ~/bin/trash

Now comes the neat part of the hack. I want this script to kick in every time I use rm . Since it is the shell that executes commands, I simply need to make my shell use the trash command instead. I do that by adding this line to ~/.cshrc:

  alias rm    trash

That line basically says: when I type rm , execute trash instead. It doesn’t matter which directory I am in. As long as I stay in my shell, it will mv any files I try to rm to my hidden trash directory.

Running the Code Safely

Whenever you create a script, always test it first. I’ll start by telling my shell to reread its configuration file:

  % source ~/.cshrc

Then, I’ll make some test files to remove:

  % cd
 
% mkdir test
  % cd test
  % touch test1
 
%
rm test1
  % ls ~/.trash
  test1 

Looks like the script is working. However, it has a flaw. Have you spotted it yet? If not, try this:

  % touch a aa aaa aaaa
 
%
rm a*
 
% ls ~/.trash
  test1          a
 
% ls test
 
aa         aaa         aaaa

What happened here? I passed the shell more than one parameter. The a* was expanded to a, aa , aaa , and aaaa before  trash could execute. Those four parameters were then passed on to the mv command in my script. However, trash passes only the first parameter to the mv command, ignoring the remaining parameters. Fortunately, they weren’t removed, but the script still didn’t achieve what I wanted.

You can actually have up to nine parameters, named $1 to $9 . However, our goal is to catch all parameters, regardless of the amount. To do that, we use $@ :

  mv $@ ~/.trash/

Make that change to your script, then test it by removing multiple files. You should now have a script that works every time.

Taking Out the Trash

You should occasionally go through your trash directory and really remove the files you no longer want. If you’re really on your toes you may be think ing, “But how do I empty the trash directory?” If you do this:

% rm ~/.trash/*

your trash directory won’t lose any files! This time you really do want to use rm, not trash. To tell your shell to use the real rm command, simply put a in front of it like so:

  % rm /trash/*

Voila, empty recycling bin.

Hacking the Hack

One obvious extension is to keep versioned backups. Use the date command to find the time of deletion and append that to the name of the file in the trash command. You could get infinitely more complicated by storing a limited number of versions or deleting all versions older than a week or a month. Of course, you could also keep your important files under version control and leave the complexity to someone else!

Please check back next week for the conclusion of this article.

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