u---unset Verified current stable Not installed? System Operations

U Unset / Remove Variable And Run Program

Remove Variable And Run Program

Removes a specified environment variable and executes a program.

$
Terminal
env -u <variable> <program>

When To Use

When isolating the effect of specific environment variables on program behavior.

Pro Tip

Use extensively when debugging application dependencies; it can prevent misconfiguration errors.

Command Builder

Tune the command before you copy it

Back to syntax
$
Generated Command
env -u <variable> <program>

Anatomy of Output

Understanding the result

Unsetting variable: MY_VAR Unset Variable

Indicates the variable that was removed.

Program executed: another_program Executed Program

Specifies the program that ran after unsetting.

Troubleshooting

Common pitfalls

Variable not found

Solution: Make sure the environment variable exists before attempting to unset.

Program not executable

Solution: Verify the program permissions and path.

Execution failed

Solution: Check for error messages that provide relevant context.

Command Breakdown

What each part is doing

env
Base Command
The executable that performs this operation. Here it runs U Unset before the shell applies any redirect operators.
-u
u| unset
The value supplied for u| unset.
<variable>
variable
The value supplied for variable.
<program>
program
The value supplied for program.
-u
Command Option
Tool-specific option used by this command invocation.

Alternative Approaches

Comparable commands in other tools

Alternative system operations tools for the same job.