Revision [1075]
This is an old revision of CommandTest made by DavidLee on 2009-11-30 11:28:17.
Command test
Synopsis
test expr[ expr ]
The test command evaluates an expression and returns true or false (0,1) as its exit value.
The test command is aliased as "[" which is the typical use.
An omitted EXPRESSION defaults to false. Otherwise, EXPRESSION is true
or false and sets exit status. It is one of:
( EXPRESSION )
EXPRESSION is true
! EXPRESSION
EXPRESSION is false
EXPRESSION1 -a EXPRESSION2
both EXPRESSION1 and EXPRESSION2 are true
EXPRESSION1 -o EXPRESSION2
either EXPRESSION1 or EXPRESSION2 is true
-n STRING
the length of STRING is nonzero
STRING
equivalent to -n STRING
-z STRING
the length of STRING is zero
-D name
true if the environment variable "name" is defined
-S value
true if the value/argument is a string type (not an xml type)
-X value
true if the value/argument is an xml type
STRING1 = STRING2
the strings are equal
STRING1 != STRING2
the strings are not equal
INTEGER1 -eq INTEGER2
INTEGER1 is equal to INTEGER2
INTEGER1 -ge INTEGER2
INTEGER1 is greater than or equal to INTEGER2
INTEGER1 -gt INTEGER2
INTEGER1 is greater than INTEGER2
INTEGER1 -le INTEGER2
INTEGER1 is less than or equal to INTEGER2
INTEGER1 -lt INTEGER2
INTEGER1 is less than INTEGER2
INTEGER1 -ne INTEGER2
INTEGER1 is not equal to INTEGER2
FILE1 -ef FILE2
FILE1 and FILE2 have the same cananocal path
FILE1 -nt FILE2
FILE1 is newer (modification date) than FILE2
FILE1 -ot FILE2
FILE1 is older than FILE2
-d FILE
FILE exists and is a directory
-e FILE
FILE exists
-f FILE
FILE exists and is a regular file
-r FILE
FILE exists and read permission is granted
-s FILE
FILE exists and has a size greater than zero
-w FILE
FILE exists and write permission is granted
-x FILE
FILE exists and execute (or search) permission is granted
-u string
TRUE if string is formated as an absolute URI (starts with <scheme>: )
Beware that parentheses need to be escaped (e.g., by back-
slashes) for shells. INTEGER may also be -l STRING, which evaluates to
the length of STRING.
XML Expressions
An XML Expression within the test command is evaluated to boolean and the result used for the expression.
A simplistic example
[ <[ fn:true() ]> ] && echo true
A more interesting example
a=<[ <foo attr="bar"/> ]> if [ <[ $a/@attr eq 'bar' ]> ] ; then echo attr is bar fi
Note the spaces needed before and after the [ and ]
Commands
CategoryCommands
