08-16-2015
Hi, for Posix compliant shells:
- There are shell variables and environment variables
- When a shell starts it makes a copy of the environment variables and creates shell variables with the same name and value, with the export attribute set (marked for export)
- If new shell variables are created in a shell, then they are not marked for export
- The export command sets the export attribute of the shell variables (marks them for export).
- A subprocess inherits all shell variables marked for export (and also variable assignments that are part of the command)
- A subshell is a special kind of subprocess that inherits all shell variables, even those not marked for export.
- The env command (since it is executed as a subprocess) shows the environment variables that would be inherited by a subprocess.
subshells are created implicitly by the shell syntax or explicitly using parentheses
( .... )
Last edited by Scrutinizer; 08-16-2015 at 04:04 PM..
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LEARN ABOUT SUNOS
asadmin-unset
asadmin-unset(1AS) User Commands asadmin-unset(1AS)
NAME
asadmin-unset, unset - removes one or more variables from the multimode environment
SYNOPSIS
unset env_var [env_var]*
Removes one or more variables you set for the multimode environment. The variables and their associated values will no longer exist in the
environment.
OPERANDS
env_var environment variable to be removed.
Example 1: Using unset to remove environment variables
asadmin> export AS_ADMIN_HOST=bluestar AS_ADMIN_PORT=8000 AS_ADMIN_USER=admin AS_ADMIN_PASSWORD=password
asadmin> export AS_ADMIN_PREFIX=server1.jms-service
asadmin> export
AS_ADMIN_HOST=bluestar
AS_ADMIN_PORT=8000
AS_ADMIN_USER=admin
AS_ADMIN_PASSWORD=********
AS_ADMIN_PREFIX=server1.jms-service
asadmin> unset AS_ADMIN_PREFIX
asadmin> export
AS_ADMIN_HOST=bluestar
AS_ADMIN_PORT=8000
AS_ADMIN_USER=admin
AS_ADMIN_PASSWORD=********
Using the export command without the argument lists the environment variables that are set. Notice the AS_ADMIN_PREFIX is not in the envi-
ronment after running the unset command.
EXIT STATUS
0 command executed successfully
1 error in executing the command
asadmin-export(1AS), asadmin-multimode(1AS)
J2EE 1.4 SDK March 2004 asadmin-unset(1AS)