4.3.5 Command execution and environment variable

Typical command execution uses a shell line sequence like the following: [28]

     $ date
     Sun Oct 26 08:17:20 CET 2003
     $ LC_ALL=fr_FR date
     dim oct 26 08:17:39 CET 2003

Here, the program date is executed in the foreground job. The environment variable LC_ALL is:

• unset (system default, same as C) for the first command

• set to fr_FR (French locale) for the second command

Most command executions usually do not have preceding environment variable definition. For the above example, you can alternatively execute:

     $ LC_ALL=fr_FR
     $ date
     dim oct 26 08:17:39 CET 2003

As you can see here, the output of command is affected by the environment variable to produce French output. If you want the environment variable to be inherited to the subprocesses (e.g., when calling shell script), you need to "export" it instead by using:

     $ export LC_ALL