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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | NOTES | AUTHOR | REPORTING BUGS | COPYRIGHT | SEE ALSO | COLOPHON |
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ENV(1) User Commands ENV(1)
env - run a program in a modified environment
env [OPTION]... [-] [NAME=VALUE]... [COMMAND [ARG]...]
Set each NAME to VALUE in the environment and run COMMAND.
Mandatory arguments to long options are mandatory for short
options too.
-a, --argv0=ARG
pass ARG as the zeroth argument of COMMAND
-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
-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 using the traditional shell trap
command. The following example ensures that seq will be
terminated 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'
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."
Written by Richard Mlynarik, David MacKenzie, and Assaf Gordon.
GNU coreutils online help:
<https://www.gnu.org/software/coreutils/>
Report any translation bugs to
<https://translationproject.org/team/>
Copyright © 2024 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.
sigaction(2), sigprocmask(2), signal(7)
Full documentation <https://www.gnu.org/software/coreutils/env>
or available locally via: info '(coreutils) env invocation'
This page is part of the coreutils (basic file, shell and text
manipulation utilities) project. Information about the project
can be found at ⟨http://www.gnu.org/software/coreutils/⟩. If you
have a bug report for this manual page, see
⟨http://www.gnu.org/software/coreutils/⟩. This page was obtained
from the tarball coreutils-9.5.tar.xz fetched from
⟨http://ftp.gnu.org/gnu/coreutils/⟩ on 2024-06-14. If you
discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for
the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original
manual page), send a mail to [email protected]
GNU coreutils 9.5 March 2024 ENV(1)
Pages that refer to this page: pmpython(1), environ(7)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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