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A page for each applet in the kit, plus .so stubs for aliases such as egrep and unxz. Each was written from the pinned busybox-w32 source with the kit's patches and configuration, then checked against the source and by experiment. The NOTES sections cover Windows behavior. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
384 lines
7.6 KiB
Groff
384 lines
7.6 KiB
Groff
.TH ENV 1 2026-10-19 "w64devkit" "w64devkit Manual"
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.SH NAME
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env \- run a program in a modified environment, or print the environment
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.SH SYNOPSIS
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.B env
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.RB [ \-i0 ]
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.RB [ \-u
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.IR name ]...\&
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.RB [ \- ]
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[\fIname\fB=\fIvalue\fR]...\&
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.RI [ prog
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.RI [ arg ...]]
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.SH DESCRIPTION
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.B env
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changes the environment it inherited, then either runs
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.I prog
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in the changed environment or, when there is no
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.IR prog ,
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prints it.
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It makes the changes in this order:
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.IP 1. 4
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With
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.B \-i
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or a lone
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.BR \- ,
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every inherited variable is removed.
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.IP 2. 4
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Each
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.B \-u
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.I name
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is removed.
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.IP 3. 4
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Each
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.IB name = value
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operand sets a variable, from left to right.
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So an assignment overrides a
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.B \-u
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of the same name.
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.PP
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After the options and any lone
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.BR \- ,
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an operand that contains an
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.B =
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is an assignment, and the first operand that does not is
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.IR prog .
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The operands after
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.I prog
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are its arguments and reach it unchanged, even if they contain an
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.BR = .
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.PP
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With
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.IR prog ,
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.B env
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runs it with its own standard input, standard output, and standard
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error, waits for it, and exits with its exit status.
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The lookup of
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.I prog
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uses the changed environment, so a
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.B PATH
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assignment takes effect, and with no
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.B PATH
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only applets and names that include a directory are found.
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The lookup follows
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.B Running commands
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in
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.BR busybox (1),
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with one difference from the shell: a
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.I prog
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of
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.IR /bin/name ,
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.IR /usr/bin/name ,
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.IR /sbin/name ,
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or
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.I /usr/sbin/name
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runs the applet
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.I name
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if there is one, or else that file if it exists, or else the program
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.I name
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in
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.BR PATH .
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.PP
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Without
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.IR prog ,
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.B env
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writes the changed environment to standard output, one variable per
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line as
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.IB name = value\fR.
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The variables it inherited come first, in the order Windows supplied
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them.
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New variables follow in the order they were added, starting with any
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.B BB_GLOBBING
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that busybox added; see
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.BR ENVIRONMENT .
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.SH OPTIONS
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Options may be grouped, as in
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.BR \-i0 .
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They are recognized only before the first operand: everything from the
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first operand on, even one that begins with a dash, is an operand.
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.B \-\-
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ends the options.
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Long options may be shortened to any unambiguous prefix.
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.TP
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.BR \-i ", " \-\-ignore\-environment
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Start with an empty environment.
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.TP
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.B \-
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Same as
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.BR \-i ,
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but an operand, not an option.
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It counts only as the first operand.
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In any later position it is an ordinary operand.
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.TP
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.BR \-0 ", " \-\-null
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Write each variable of the listing followed by a NUL octet instead of a
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LF.
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It has no effect when
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.I prog
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runs.
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.TP
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\fB\-u\fR \fIname\fR, \fB\-\-unset\fR \fIname\fR
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Remove the variable
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.I name
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from the environment.
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The option may be repeated.
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Removing a variable that is not set is not an error.
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The argument of the short option may be attached, as in
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.BR \-uPATH ,
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and the long option also takes it as
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.BI \-\-unset= name\fR.
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An argument that contains an
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.B =
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is not a name: it sets that variable, as an assignment would, and
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removes nothing.
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.TP
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.B \-\-help
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Print a usage message on standard output and exit with status 0.
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It is recognized only as the first argument, and any further arguments
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are ignored.
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.SH ENVIRONMENT
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Except for
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.BR BB_GLOBBING ,
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these are read from the changed environment, so the options and
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assignments affect them.
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.TP
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.B BB_GLOBBING
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Unless it is
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.BR 0 ,
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busybox expands wildcards in the arguments of
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.B env
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itself when it starts, as needed when run from
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.BR cmd.exe .
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If the variable is not set then, busybox sets it to
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.BR 0 .
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Because
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.B env
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passes its environment on, the listing then includes
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.B BB_GLOBBING=0
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and so does
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.IR prog 's
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environment, unless
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.B \-i
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or
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.B \-u
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removed it.
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Without it, an applet run as
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.I prog
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expands wildcards in its arguments again, so
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.B env \-i ls \(aq*.c\(aq
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lists the matching files.
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.TP
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.B BB_OVERRIDE_APPLETS
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Which names run an applet and which run a program from
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.BR PATH ;
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see
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.BR busybox (1).
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.TP
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.BR BB_TERMINAL_MODE ", " BB_SKIP_ANSI_EMULATION
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When standard output is a console, decide whether the console or busybox
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interprets the escape sequences in the listing, such as for color.
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See
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.BR busybox (1).
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.TP
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.B CONEMUPID
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When it is set and neither of the above is, busybox uses terminal mode
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0: it turns virtual terminal output off and emulates escape sequences
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itself.
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.TP
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.BR LC_ALL ", " LC_CTYPE ", " LANG
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If the first of these that is set has the value
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.BR C ,
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the listing is written to a console without code page conversion, and
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the console interprets the bytes in its own code page.
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.TP
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.B PATH
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Where
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.I prog
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is looked up.
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Directories are separated by semicolons.
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.PP
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Variables that affect every busybox applet are described in
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.BR busybox (1).
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.SH EXIT STATUS
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.TP
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.B 0
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The environment was printed.
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.TP
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.B 1
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An invalid option, or an option without its argument, with a usage
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message on standard error.
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Also an operand that cannot be set as a variable, such as one that
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begins with
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.BR = ,
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with the message
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.BR "env: putenv: Invalid argument" ,
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or an error writing standard output.
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.TP
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.B 126
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.I prog
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was found but could not be started.
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.TP
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.B 127
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.I prog
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was not found.
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.PP
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For both of the last two, standard error gets
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.PP
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.RS 4
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.EX
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env: can\(aqt execute \(aq\fIprog\fR\(aq: \fIreason\fR
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.EE
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.RE
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.PP
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Otherwise the status is that of
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.IR prog ;
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see
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.BR NOTES .
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.SH EXAMPLES
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Run
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.B make
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with a variable set for that run only:
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.PP
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.RS 4
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.EX
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$ env CFLAGS=\-O2 make
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.EE
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.RE
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.PP
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Run a command with a minimal environment:
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.PP
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.RS 4
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.EX
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$ env \-i PATH="$PATH" make
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.EE
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.RE
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.PP
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Run a command without a variable:
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.PP
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.RS 4
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.EX
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$ env \-u MAKEFLAGS make
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.EE
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.RE
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.PP
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Show the environment that the options and assignments build:
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.PP
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.RS 4
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.EX
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$ env \-i FOO=1 BAR=2
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FOO=1
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BAR=2
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.EE
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.RE
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.PP
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Count the variables, correctly even for values that contain newlines:
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.PP
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.RS 4
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.EX
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$ env \-0 | tr \-cd \(aq\e0\(aq | wc \-c
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.EE
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.RE
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.SH NOTES
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Windows has no exec.
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.B env
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starts
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.I prog
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as a child process, waits for it, and exits with its exit code.
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A code above 255, such as an NTSTATUS value, is reduced to its low
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byte, or to 255 when that is zero, after
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.B env
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writes a message giving the code in hex to standard error.
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The codes that busybox treats as signals, such as an access violation
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and Ctrl+C, are passed on unchanged.
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.PP
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While
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.I prog
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runs, Ctrl+C and Ctrl+Break do not end
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.BR env .
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A
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.I prog
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attached to the console receives them itself, and any other
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.I prog
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is ended, with its child processes, as if by
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.BR SIGINT .
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.PP
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A
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.I prog
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that is not found is reported with status 127.
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So is one that busybox does not consider executable: a directory, or a
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file that has none of the suffixes
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.BR .com ,
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.BR .exe ,
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.BR .sh ,
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.BR .bat ,
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and
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.BR .cmd ,
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does not begin with
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.BR #!\& ,
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and is not a PE image.
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A file that busybox considers executable but that Windows cannot run,
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such as an
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.I .exe
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that is not a valid program, gives status 126.
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.PP
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Variable names are case-insensitive.
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An assignment to
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.B Path
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replaces
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.BR PATH ,
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and
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.B \-u path
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removes it.
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The name takes the spelling of the assignment.
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.PP
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A variable may have an empty value, as in
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.IB name =\fR,
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which
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.B env
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keeps and passes on.
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A name may not be empty: an operand that begins with
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.B =
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fails.
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.PP
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busybox runs this applet for a
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.B #!/usr/bin/env
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line in a script, so a line such as
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.B #!/usr/bin/env sh
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works; see
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.BR busybox (1).
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The rest of the line after the interpreter is a single argument, so
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.B #!/usr/bin/env \-i sh
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fails.
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.PP
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Differences from GNU
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.BR env :
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only
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.BR \-i ,
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.BR \-0 ,
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.BR \-u ,
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and their long forms exist, so there is no
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.BR \-C ,
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.BR \-S ,
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or
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.BR \-v ,
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and there is no
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.BR \-\-version .
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An argument of
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.B \-u
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that contains an
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.B =
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sets a variable, and
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.B \-0
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with
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.I prog
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is accepted.
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An invalid option gives status 1, not 125.
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.PP
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The listing ends each line with a bare LF, not CR LF.
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.SH SEE ALSO
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.BR busybox (1),
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.BR printenv (1),
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.BR sh (1),
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.BR tr (1),
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.BR wc (1)
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