test.1sh5

<B>Digital的Unix操作系统VAX 4.2源码</B>

.TH test 1sh5
.SH Name
test \- condition evaluation command
.SH Syntax
.B test
expr
.br
.B [
expr
.B ]
.SH Description
.NXR "test command" "command programming language"
The
.PN test
command evaluates the expression
.I expr.
If the value of
.I expr
is true, the 
.PN test 
command returns a zero exit status; otherwise, it
returns a nonzero exit status.  The
.PN test
command also
returns a nonzero exit status if no arguments are specified.
The following primitives are used to construct
.IR expr  :
.TP 15
.BI \-r " file\^"
True if \fIfile\fR exists and is readable.
.TP
.BI \-w " file\^"
True if \fIfile\fR exists and is writable.
.TP
.BI \-x " file\^"
True if
.I file\^
exists and is executable.
.TP
.BI \-f " file\^"
True if \fIfile\fR exists and is a regular file.
.TP
.BI \-d " file\^"
True if \fIfile\fR exists and is a directory.
.TP
.BI \-c " file\^"
True
if
.I file\^
exists and is a character special file.
.TP
.BI \-b " file\^"
True if
.I file\^
exists and is a block special file.
.TP
.BI \-p " file\^"
True if
.I file\^
exists and is a named pipe (fifo).
.TP
.BI \-u " file\^"
True if
.I file\^
exists and its set-user-\c
.SM ID
bit is set.
.TP
.BI \-g " file\^"
True if
.I file\^
exists and its set-group-\c
.SM ID
bit is set.
.TP
.BI \-k " file\^"
True if
.I file\^
exists and its sticky bit is set.
.TP
.BI \-s " file\^"
True if \fIfile\fR exists and has a size greater than zero.
.TP
.BR \-t " [ \fIfildes\fR ]"
True if the open file whose file descriptor number is
.I fildes\^
(1 by default)
is associated with a terminal device.
.TP
.BI \-z " s1\^"
True if the length of string
.I s1\^
is zero.
.TP
.BI \-n " s1\^"
True if the length of the string
.I s1\^
is non-zero.
.TP
.IB s1 " = " s2\^
True
if strings
.I s1\^
and
.I s2\^
are identical.
.TP
.IB s1 " != " s2\^
True
if strings
.I s1\^
and
.I s2\^
are
.I not\^
identical.
.TP
.I s1\^
True if
.I s1\^
is
.I not\^
the null string.
.TP
.IB n1 " \-eq " n2\^
True if the integers
.I n1\^
and
.I n2\^
are algebraically equal.
Any of the comparisons
.BR \-ne ,
.BR \-gt ,
.BR \-ge ,
.BR \-lt ,
and
.BR \-le
may be used in place of
.BR \-eq .
.PP
These primitives can be combined with the
following operators:
.TP 15
.B  !
unary negation operator.
.TP
.B  \-a
binary
.I and\^
operator.
.TP
.B  \-o
binary
.I or\^
operator
.RB ( \-a
has higher precedence than
.BR \-o ).
.TP
.BR "(\| " "expr" " \|)"
parentheses for grouping.
.PP
Note that all the operators and flags are separate
arguments to the
.PN test 
command.  Note also that parentheses are meaningful
to the Shell and must be escaped.
.NT Note
In the form of the command that uses
square brackets ([\|]),
instead of the word
.IR test ,
the brackets must be delimited by blanks.
.SH See Also
find(1), sh5(1), test(1)