coreutils (9.4)
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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=NAME
remove variable from the environment
-C, --chdir=DIR
change working directory to DIR
-S, --split-string=S
process and split S into separate arguments; used to pass multiple arguments on shebang 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 signal(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. An empty SIG argument is a no-op.
Exit status:
125 if the env command itself fails
126 if COMMAND is found but cannot be invoked
127 if COMMAND cannot be found
- the exit status of COMMAND otherwise
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 fol‐
lowing 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 using the traditional
shell trap command. The following example ensures that seq will be terminated by SIGPIPE no matter how this sig‐
nal is being handled in the process invoking the command.
sh -c 'env --default-signal=PIPE seq inf | head -n1'
NOTES
POSIX's exec(3p) 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 © 2023 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/li‐
censes/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), sigprocmask(2), signal(7)
Full documentation <https://www.gnu.org/software/coreutils/env>
or available locally via: info '(coreutils) env invocation'
GNU coreutils 9.4 August 2023 ENV(1)
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=NAME
remove variable from the environment
-C, --chdir=DIR
change working directory to DIR
-S, --split-string=S
process and split S into separate arguments; used to pass multiple arguments on shebang 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 signal(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. An empty SIG argument is a no-op.
Exit status:
125 if the env command itself fails
126 if COMMAND is found but cannot be invoked
127 if COMMAND cannot be found
- the exit status of COMMAND otherwise
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 fol‐
lowing 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 using the traditional
shell trap command. The following example ensures that seq will be terminated by SIGPIPE no matter how this sig‐
nal is being handled in the process invoking the command.
sh -c 'env --default-signal=PIPE seq inf | head -n1'
NOTES
POSIX's exec(3p) 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 © 2023 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/li‐
censes/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), sigprocmask(2), signal(7)
Full documentation <https://www.gnu.org/software/coreutils/env>
or available locally via: info '(coreutils) env invocation'
GNU coreutils 9.4 August 2023 ENV(1)