test.1

klibc精简化的c程序库

.\" Copyright (c) 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\" Copyright (c) 1997-2005
.\"	Herbert Xu <[e-mail]>.  All rights reserved.
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.\" This code is derived from software contributed to Berkeley by
.\" the Institute of Electrical and Electronics Engineers, Inc.
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.\"     @(#)test.1	8.1 (Berkeley) 5/31/93
.\"
.Dd May 31, 1993
.Dt TEST 1
.Os
.Sh NAME
.Nm test ,
.Nm \&[
.Nd condition evaluation utility
.Sh SYNOPSIS
.Nm test
.Ar expression
.Nm \&[
.Ar expression Cm ]
.Sh DESCRIPTION
The
.Nm test
utility evaluates the expression and, if it evaluates
to true, returns a zero (true) exit status; otherwise
it returns 1 (false).
If there is no expression, test also
returns 1 (false).
.Pp
All operators and flags are separate arguments to the
.Nm test
utility.
.Pp
The following primaries are used to construct expression:
.Bl -tag -width Ar
.It Fl b Ar file
True if
.Ar file
exists and is a block special
file.
.It Fl c Ar file
True if
.Ar file
exists and is a character
special file.
.It Fl d Ar file
True if
.Ar file
exists and is a directory.
.It Fl e Ar file
True if
.Ar file
exists (regardless of type).
.It Fl f Ar file
True if
.Ar file
exists and is a regular file.
.It Fl g Ar file
True if
.Ar file
exists and its set group ID flag
is set.
.It Fl h Ar file
True if
.Ar file
exists and is a symbolic link.
.It Fl k Ar file
True if
.Ar file
exists and its sticky bit is set.
.It Fl n Ar string
True if the length of
.Ar string
is nonzero.
.It Fl p Ar file
True if
.Ar file
is a named pipe
.Po Tn FIFO Pc .
.It Fl r Ar file
True if
.Ar file
exists and is readable.
.It Fl s Ar file
True if
.Ar file
exists and has a size greater
than zero.
.It Fl t Ar file_descriptor
True if the file whose file descriptor number
is
.Ar file_descriptor
is open and is associated with a terminal.
.It Fl u Ar file
True if
.Ar file
exists and its set user ID flag
is set.
.It Fl w Ar file
True if
.Ar file
exists and is writable.
True
indicates only that the write flag is on.
The file is not writable on a read-only file
system even if this test indicates true.
.It Fl x Ar file
True if
.Ar file
exists and is executable.
True
indicates only that the execute flag is on.
If
.Ar file
is a directory, true indicates that
.Ar file
can be searched.
.It Fl z Ar string
True if the length of
.Ar string
is zero.
.It Fl L Ar file
True if
.Ar file
exists and is a symbolic link.
This operator is retained for compatibility with previous versions of
this program.
Do not rely on its existence; use
.Fl h
instead.
.It Fl O Ar file
True if
.Ar file
exists and its owner matches the effective user id of this process.
.It Fl G Ar file
True if
.Ar file
exists and its group matches the effective group id of this process.
.It Fl S Ar file
True if
.Ar file
exists and is a socket.
.It Ar file1 Fl nt Ar file2
True if
.Ar file1
exists and is newer than
.Ar file2 .
.It Ar file1 Fl ot Ar file2
True if
.Ar file1
exists and is older than
.Ar file2 .
.It Ar file1 Fl ef Ar file2
True if
.Ar file1
and
.Ar file2
exist and refer to the same file.
.It Ar string
True if
.Ar string
is not the null
string.
.It Ar \&s\&1 Cm \&= Ar \&s\&2
True if the strings
.Ar \&s\&1
and
.Ar \&s\&2
are identical.
.It Ar \&s\&1 Cm \&!= Ar \&s\&2
True if the strings
.Ar \&s\&1
and
.Ar \&s\&2
are not identical.
.It Ar \&s\&1 Cm \&\*[Lt] Ar \&s\&2
True if string
.Ar \&s\&1
comes before
.Ar \&s\&2
based on the ASCII value of their characters.
.It Ar \&s\&1 Cm \&\*[Gt] Ar \&s\&2
True if string
.Ar \&s\&1
comes after
.Ar \&s\&2
based on the ASCII value of their characters.
.It Ar \&n\&1 Fl \&eq Ar \&n\&2
True if the integers
.Ar \&n\&1
and
.Ar \&n\&2
are algebraically
equal.
.It Ar \&n\&1 Fl \&ne Ar \&n\&2
True if the integers
.Ar \&n\&1
and
.Ar \&n\&2
are not
algebraically equal.
.It Ar \&n\&1 Fl \&gt Ar \&n\&2
True if the integer
.Ar \&n\&1
is algebraically
greater than the integer
.Ar \&n\&2 .
.It Ar \&n\&1 Fl \&ge Ar \&n\&2
True if the integer
.Ar \&n\&1
is algebraically
greater than or equal to the integer
.Ar \&n\&2 .
.It Ar \&n\&1 Fl \&lt Ar \&n\&2
True if the integer
.Ar \&n\&1
is algebraically less
than the integer
.Ar \&n\&2 .
.It Ar \&n\&1 Fl \&le Ar \&n\&2
True if the integer
.Ar \&n\&1
is algebraically less
than or equal to the integer
.Ar \&n\&2 .
.El
.Pp
These primaries can be combined with the following operators:
.Bl -tag -width Ar
.It Cm \&! Ar expression
True if
.Ar expression
is false.
.It Ar expression1 Fl a Ar expression2
True if both
.Ar expression1
and
.Ar expression2
are true.
.It Ar expression1 Fl o Ar expression2
True if either
.Ar expression1
or
.Ar expression2
are true.
.It Cm \&( Ns Ar expression Ns Cm \&)
True if expression is true.
.El
.Pp
The
.Fl a
operator has higher precedence than the
.Fl o
operator.
.Sh GRAMMAR AMBIGUITY
The
.Nm test
grammar is inherently ambiguous.
In order to assure a degree of consistency, the cases described in
.St -p1003.2
section 4.62.4,
are evaluated consistently according to the rules specified in the
standards document.
All other cases are subject to the ambiguity in the command semantics.
.Sh EXIT STATUS
The
.Nm test
utility exits with one of the following values:
.Bl -tag -width Ds
.It 0
expression evaluated to true.
.It 1
expression evaluated to false or expression was
missing.
.It \*[Gt]1
An error occurred.
.El
.Sh STANDARDS
The
.Nm test
utility implements a superset of the
.St -p1003.2
specification.