index.txt
TEST(1) General Commands Manual TEST(1) NAME test - condition command SYNOPSIS test expr DESCRIPTION test evaluates the expression expr, and if its value is true then re‐ turns zero exit status; otherwise, a non zero exit status is returned. test returns a non zero exit if there are no arguments. The following primitives are used to construct expr. -r file true if the file exists and is readable. -w file true if the file exists and is writable. -f file true if the file exists and is not a directory. -d file true if the file exists and is a directory. -s file true if the file exists and has a size greater than zero. -t [ fildes ] true if the open file whose file descriptor number is fildes (1 by default) is associated with a terminal device. -z s1 true if the length of string s1 is zero. -n s1 true if the length of the string s1 is nonzero. s1 = s2 true if the strings s1 and s2 are equal. s1 != s2 true if the strings s1 and s2 are not equal. s1 true if s1 is not the null string. n1 -eq n2 true if the integers n1 and n2 are algebraically equal. Any of the comparisons -ne, -gt, -ge, -lt, or -le may be used in place of -eq. These primaries may be combined with the following operators: ! unary negation operator -a binary and operator -o binary or operator ( expr ) parentheses for grouping. -a has higher precedence than -o. Notice that all the operators and flags are separate arguments to test. Notice also that parentheses are meaningful to the Shell and must be escaped. SEE ALSO sh(1), find(1) TEST(1)