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| [9] | 1 | .TH ENV 1
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| 2 | .SH NAME
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| 3 | env \- set environment for command
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| 4 | .SH SYNOPSIS
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| 5 | .B env
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| 6 | .RB [ \-ia ]
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| 7 | .RI [ name\fB=\fIvalue "] ..."
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| 8 | .RI [ utility
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| 9 | .RI [ argument "...]]"
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| 10 | .SH DESCRIPTION
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| 11 | .B Env
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| 12 | modifies its environment according to the
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| 13 | .IB name = value
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| 14 | arguments, and executes
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| 15 | .I utility
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| 16 | with the given arguments and the modified environment.
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| 17 | .PP
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| 18 | If no utility is specified then the modified environment is printed as
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| 19 | .IB name = value
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| 20 | strings, one per line.
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| 21 | .SH OPTIONS
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| 22 | .TP
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| 23 | .B \-i
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| 24 | Use exactly the environment specified by the arguments; the inherited
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| 25 | environment is ignored.
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| 26 | .TP
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| 27 | .B \-a
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| 28 | Specify all arguments for the utility, i.e. the first of the arguments is
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| 29 | used as
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| 30 | .BR "argv[0]" ,
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| 31 | the program name. Normally the program name is
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| 32 | .I utility
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| 33 | itself.
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| 34 | .SH ENVIRONMENT
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| 35 | .TP 8n
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| 36 | .B PATH
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| 37 | The path used to find utility. It is as modified by
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| 38 | .BR env ,
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| 39 | i.e.
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| 40 | .B not
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| 41 | the inherited
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| 42 | .BR PATH .
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| 43 | .SH "SEE ALSO"
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| 44 | .BR sh (1),
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| 45 | .BR execvp (3),
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| 46 | .BR environ (5).
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| 47 | .SH DIAGNOSTICS
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| 48 | The return code is
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| 49 | .B 0
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| 50 | after successfully printing the environment,
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| 51 | .B 1
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| 52 | on an error within
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| 53 | .BR env ,
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| 54 | .B 126
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| 55 | if the
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| 56 | .I utility
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| 57 | could not be executed, or
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| 58 | .B 127
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| 59 | if
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| 60 | .I utility
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| 61 | could not be found. Appropriate diagnostic messages are printed on standard
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| 62 | error.
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| 63 | If
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| 64 | .I utility
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| 65 | can be executed then it replaces
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| 66 | .BR env ,
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| 67 | so the return code is then the return code of
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| 68 | .IR utility .
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| 69 | .SH NOTES
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| 70 | When run from the standard shell
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| 71 | .B env
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| 72 | is only useful with options or without arguments. Otherwise the shell can
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| 73 | do exactly what
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| 74 | .B env
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| 75 | can do, simply omit the word "env" on the command line.
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| 76 | .PP
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| 77 | One interesting use of
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| 78 | .B env
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| 79 | is with #! on the first line of a script to forge a PATH search for an
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| 80 | interpreter. For example:
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| 81 | .PP
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| 82 | .RS
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| 83 | #!/usr/bin/env perl
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| 84 | .RE
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| 85 | .PP
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| 86 | This will find the Perl interpreter if it is within the user's PATH. Most
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| 87 | UNIX-like systems have
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| 88 | .B env
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| 89 | in /usr/bin, but
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| 90 | .B perl
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| 91 | may be anywhere.
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| 92 | .SH AUTHOR
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| 93 | Kees J. Bot <kjb@cs.vu.nl>
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