manpagez: man pages & more
man env(1)
Home | html | info | man
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 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.  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(2) 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  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  (C) 2019 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 8.31                March 2019                            env(1)

coreutils 8.31 - Generated Tue Mar 12 15:04:06 CDT 2019
© manpagez.com 2000-2019
Individual documents may contain additional copyright information.