.TH TEST 1 .SH NAME test \- condition command .SH SYNOPSIS .B test expr .SH DESCRIPTION .I test evaluates the expression .IR expr , and if its value is true then returns zero exit status; otherwise, a non zero exit status is returned. .I test returns a non zero exit if there are no arguments. .PP The following primitives are used to construct .IR expr . .TP 9n .BR \-r " file" true if the file exists and is readable. .TP .BR \-w " file" true if the file exists and is writable. .TP .BR \-f " file" true if the file exists and is not a directory. .TP .BR \-d " file" true if the file exists and is a directory. .TP .BR \-s " file" true if the file exists and has a size greater than zero. .TP .BR \-t " [ fildes ]" true if the open file whose file descriptor number is .I fildes (1 by default) is associated with a terminal device. .TP .BR \-z " s1" true if the length of string .I s1 is zero. .TP .BR \-n " s1" true if the length of the string .I s1 is nonzero. .TP .RB s1 " = " s2 true if the strings .I s1 and .I s2 are equal. .TP .RB s1 " != " s2 true if the strings .I s1 and .I s2 are not equal. .TP s1 true if .I s1 is not the null string. .TP .RB 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 , or .BR \-le may be used in place of .BR \-eq . .PP These primaries may be combined with the following operators: .TP .B ! unary negation operator .TP .B \-a binary .I and operator .TP .B \-o binary .I or operator .TP .BR "( " "expr" " )" parentheses for grouping. .PP .B \-a has higher precedence than .B \-o. Notice that all the operators and flags are separate arguments to .IR test . Notice also that parentheses are meaningful to the Shell and must be escaped. .SH "SEE ALSO" sh(1), find(1)
