# phpman > man > ENV(1)

> **TLDR:** Show the environment or run a program in a modified environment.
>
- Show the environment:
  `env`
- Run a program. Often used in scripts after the shebang (#!) for looking up the path to the program:
  `env {{program}}`
- Clear the environment and run a program:
  `env {{-i|--ignore-environment}} {{program}}`
- Remove variable from the environment and run a program:
  `env {{-u|--unset}} {{variable}} {{program}}`
- Set a variable and run a program:
  `env {{variable}}={{value}} {{program}}`
- Set one or more variables and run a program:
  `env {{variable1=value variable2=value variable3=value ...}} {{program}}`
- Run a program under a different name:
  `env {{-a|--argv0}} {{custom_name}} {{program}}`

*Source: tldr-pages*

---

[ENV(1)](https://www.chedong.com/phpMan.php/man/ENV/1/markdown)                                      User Commands                                     [ENV(1)](https://www.chedong.com/phpMan.php/man/ENV/1/markdown)



## NAME
       env - run a program in a modified environment

## SYNOPSIS
       **env** [_OPTION_]... [_-_] [_NAME=VALUE_]... [_COMMAND_ [_ARG_]...]

## DESCRIPTION
       Set each NAME to VALUE in the environment and run COMMAND.

       Mandatory arguments to long options are mandatory for short options too.

### -i --ignore-environment
              start with an empty environment

### -0 --null
              end each output line with NUL, not newline

### -u --unset
              remove variable from the environment

### -C --chdir
              change working directory to DIR

### -S --split-string
              process  and  split S into separate arguments; used to pass multiple arguments on she‐
              bang lines

       **--block-signal**[=_SIG_]
              block delivery of SIG signal(s) to COMMAND

       **--default-signal**[=_SIG_]
              reset handling of SIG signal(s) to the default

       **--ignore-signal**[=_SIG_]
              set handling of SIG signals(s) to do nothing

### --list-signal-handling
              list non default signal handling to stderr

### -v --debug
              print verbose information for each processing step

       **--help** display this help and exit

### --version
              output version information and exit

       A mere - implies **-i**.  If no COMMAND, print the resulting environment.

       SIG may be a signal name like 'PIPE', or a signal number like '13'.  Without SIG,  all  known
       signals are included.  Multiple signals can be comma-separated.

## OPTIONS
### -S/--split-string usage in scripts
       The **-S** option allows specifying multiple parameters in a script.  Running a script named **1.pl**
       containing the following first line:

              #!/usr/bin/env -S perl -w -T
              ...

       Will execute **perl** **-w** **-T** **1.pl** **.**

       Without the **'-S'** parameter the script will likely fail with:

              /usr/bin/env: 'perl -w -T': No such file or directory

       See the full documentation for more details.

### --default-signal[=SIG] usage
       This option allows setting a signal handler to its default action, which is not possible  us‐
       ing  the traditional shell trap command.  The following example ensures that seq will be ter‐
       minated by SIGPIPE no matter how this signal is being handled in  the  process  invoking  the
       command.


              sh -c 'env --default-signal=PIPE seq inf | head -n1'

## NOTES
       POSIX's [exec(2)](https://www.chedong.com/phpMan.php/man/exec/2/markdown) pages says:
              "many existing applications wrongly assume that they start with certain signals set to
              the default action and/or unblocked.... Therefore, it is best not to block  or  ignore
              signals  across  execs  without  explicit reason to do so, and especially not to block
              signals across execs of arbitrary (not closely cooperating) programs."

## AUTHOR
       Written by Richard Mlynarik, David MacKenzie, and Assaf Gordon.

## REPORTING BUGS
       GNU coreutils online help: <<https://www.gnu.org/software/coreutils/>>
       Report any translation bugs to <<https://translationproject.org/team/>>

## COPYRIGHT
       Copyright © 2020 Free Software Foundation, Inc.  License GPLv3+: GNU GPL version 3  or  later
       <<https://gnu.org/licenses/gpl.html>>.
       This  is free software: you are free to change and redistribute it.  There is NO WARRANTY, to
       the extent permitted by law.

## SEE ALSO
       [sigaction(2)](https://www.chedong.com/phpMan.php/man/sigaction/2/markdown), [sigprocmask(2)](https://www.chedong.com/phpMan.php/man/sigprocmask/2/markdown), [signal(7)](https://www.chedong.com/phpMan.php/man/signal/7/markdown)

       Full documentation <<https://www.gnu.org/software/coreutils/env>>
       or available locally via: info '(coreutils) env invocation'



GNU coreutils 8.32                          January 2026                                      [ENV(1)](https://www.chedong.com/phpMan.php/man/ENV/1/markdown)