ENV(1) User Commands 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 multi-
ple 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.
OPTIONS
-S/--split-string usage in scripts
The -S option allows specifying multiple parameters in a script. Run-
ning 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'
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 ex-
ecs without explicit reason to do so, and especially not to
block signals across execs of arbitrary (not closely cooperat-
ing) 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 © 2022 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), sigprocmask(2), signal(7)
Full documentation <https://www.gnu.org/software/coreutils/env>
or available locally via: info '(coreutils) env invocation'
GNU coreutils 9.1 September 2022 ENV(1)
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