From: Bastien Roucariès <ro...@debian.org> Compare with argc/argv and describe the purpose of environment --- man7/environ.7 | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)
diff --git a/man7/environ.7 b/man7/environ.7 index 7eeb1fe0e..f9e49a572 100644 --- a/man7/environ.7 +++ b/man7/environ.7 @@ -66,6 +66,30 @@ if the feature test macro is defined (see .BR feature_test_macros(7)). .PP +At time of execution, a program receives context information by two mechanisms. +The first way is the program arguments, represented by the +.I argc +and +.I argv +arguments of the +.I main +function. The second is the +.I environ +variable as discussed in this manual. +.PP +The program arguments are typically used to pass so-called +command-line arguments specific to a particular use of the program +being invoked, thus changing the program's behavior for this use case. +The environment, on the other hand, keeps track of information that is shared by many programs and +rarely changes. For example, a running process can query the value of the +.B TMDIR +environment variable to discover a suitable location to store temporary files. +.PP +Standard environment variables are used for information about the user' home directory, +current language, etc., and a user can define additional variables for other purposes. +The set of all environment variables that have values is collectively known as +the process environment or simply the environment. +.PP This array of strings is made available to the process by the .BR exec (3) call that started the process. -- 2.29.2
