Customizing a User's Work Environment

Part of setting up a user's home directory is providing user initialization files for the user's login shell. A user initialization file is a shell script that sets up a work environment for a user after the user logs in to a system. Basically, you can perform any task in a user initialization file that you can do in a shell script, but its primary job is to define the characteristics of a user's work environment, such as a user's search path, environment variables, and windowing environment. Each login shell has its own user initialization file (or files), which are listed in the following table.

Table 4-16 User Initialization Files for Bourne, C, and Korn Shells

The Solaris environment provides default user initialization files for each shell in the /etc/skel directory on each system, as shown in the following table.

Table 4-17 Default User Initialization Files

You can use these files as a starting point and modify them to create a standard set of files that provide the work environment common to all users, or you can modify them to provide the working environment for different types of users. For step-by-step instructions on how to create sets of user initialization files for different types of users, see "How to Customize User Initialization Files".

When you use the Users Tool to create a new user account and select the create home directory option, the following files are created, depending on which login shell is selected:

If you use the useradd command to add a new user account and specify the /etc/skel directory by using the -k and -m options, all three /etc/skel/local* and /etc/skel/.profile files are copied into the user's home directory. At this point, you'll need to rename them to whatever is appropriate for the user's login shell.

Using Site Initialization Files

The user initialization files can be customized by both the administrator and the user. This important feature can be accomplished with centrally located and globally distributed user initialization files, called site initialization files. Site initialization files enable you to continually introduce new functionality to the user's work environment, while enabling the user to customize the user's initialization file.

When you reference a site initialization file in a user initialization file, all updates to the site initialization file are automatically reflected when the user logs in to the system or when a user starts a new shell. Site initialization files are designed for you to distribute site-wide changes to users' work environments that you did not anticipate when you added the users.

Any customization that can be done in a user initialization file can be done in a site initialization file. These files typically reside on a server (or set of servers), and appear as the first statement in a user initialization file. Also, each site initialization file must be the same type of shell script as the user initialization file that references it.

To reference a site initialization file in a C-shell user initialization file, place a line similar to the following at the beginning of the user initialization file:

source /net/machine-name/export/site-files/site-init-file

To reference a site initialization file in a Bourne- or Korn-shell user initialization file, place a line similar to the following at the beginning of the user initialization file:

. /net/machine-name/export/site-files/site-init-file

Avoid Local System References

You should not add specific references to the local system in the user's initialization file. You want the instructions in a user initialization file to be valid regardless of the system to which the user logs in. For example:

• To make a user's home directory available anywhere on the network, always refer to the home directory with the variable $HOME. For example, use $HOME/bin instead of /export/home/username/bin. $HOME works when the user logs in to another system and the home directories are automounted.

• To access files on a local disk, use global path names, like /net/system-name/directory-name. Any directory referenced by /net/system-name can be mounted automatically on any system on which the user logs in, assuming the system is running AutoFS.

Shell Features

The following table lists basic shell features that each shell provides, which can help you determine what you can and can't do when creating user initialization files for each shell.

Table 4-18 Basic Features of Bourne, C, and Korn Shells

Shell Environment

A shell maintains an environment that includes a set of variables defined by the login program, the system initialization file, and the user initialization files. In addition, some variables are defined by default. A shell can have two types of variables:

• Environment variables - Variables that are exported to all processes spawned by the shell. Their settings can be seen with the env command. A subset of environment variables, like PATH, affects the behavior of the shell itself.

• Shell (local) variables - Variables that affect only the current shell. In the C shell, a set of these shell variables have a special relationship to a corresponding set of environment variables. These shell variables are user, term, home, and path. The value of the environment variable counterpart is initially used to set the shell variable.

In the C shell, you use the lowercase names with the set command to set shell variables and use uppercase names with the setenv command to set environment variables. If you set a shell variable, the shell sets the corresponding environment variable and vice versa. For example, if you update the path shell variable with a new path, the shell also updates the PATH environment variable with the new path.

In the Bourne and Korn shells, you use the uppercase names with the setenv command to set both shell and environment variables. You also have to use the export command to finish setting environment variables. For all shells, you generally refer to shell and environment variables by their uppercase names.

In a user initialization file, you can customize a user's shell environment by changing the values of the predefined variables or by specifying additional variables. The following table shows how to set environment variables in a user initialization file.

Table 4-19 Setting Environment Variables in a User Initialization File

The following table describes environment and shell variables you might want to customize in a user initialization file. For more information about variables used by the different shells, see sh(1), ksh(1), or csh(1).

Table 4-20 Shell and Environment Variable Descriptions

The PATH Variable

When the user executes a command by using the full path, the shell uses that path to find the command. However, when users specify only a command name, the shell searches the directories for the command in the order specified by the PATH variable. If the command is found in one of the directories, the shell executes it.

A default path is set by the system, but most users modify it to add other command directories. Many user problems related to setting up the environment and accessing the right version of a command or a tool can be traced to incorrectly defined paths.