env
Processes and system
Usage
env [VAR=value] [command]Prints the whole environment, or runs one command with extra variables attached; those variables apply to that single run only and nothing is left behind in your shell.
Common flags
| Flag | Meaning |
|---|---|
| env | With no arguments, print the whole environment. |
| VAR=value <command> | Run the command with that variable added, for this run only. |
| -i | Start from an empty environment, inheriting nothing. |
| -u <VAR> | Unset one variable for the child process. |
Examples
env | sort | grep -i proxyFind the proxy variables that are breaking a download.
env NODE_ENV=production node app.jsSet a variable for one run without touching your shell.
env -i bash --noprofile --norcA shell with nothing inherited, for reproducing a cron failure.
What is running and what is eating the machine. Identifying it comes before killing it.
How to read this
- Square brackets [ ] mark a part you may leave out.
- An ellipsis … means you can list more than one.
- Flags are case-sensitive — in some commands -r and -R do different things.
Questions
Q. What does env do?
Prints the whole environment, or runs one command with extra variables attached; those variables apply to that single run only and nothing is left behind in your shell.
Q. How do I type it?
env [VAR=value] [command] — square brackets mark the parts you can leave out.
Q. How many flags are worth knowing?
4 are listed here; the full set is in man env. This command sits under Processes and system.
Related commands
man page: man env