Hamilton C shell Language Reference



Expression Operators

In order of decreasing precedence:

Operator
Meaning
( ) Grouping or Procedure call arguments
{ } Run the enclosed statement list and return 1 if it succeeds or 0 otherwise.
[ ] Array indexing. (The first element is element 0.)
-A   -C   -D   -H   -R   -S   -d   -e   -f   -o   -w   -x   -z
File system tests
++    -- Prefix and postfix increment/decrement
~   -   !   + Bitwise, arithmetic and logical complements and unary plus
** Exponentiation
*   /   %   // Multiplication, Division, Remainder and Integer Division
+   - Addition and Subtraction
<<   >> Bit-Shifting
==   !=   =~   !~   <   <=   >=   > Relation-testing and pattern-matching operators
& Bit And
^ Bit Xor
| Bit Or
&& Logical And
|| Logical Or
?: Conditional selection
=   +=   -=   *=   /=   %=   //=   >>=   <<=   &=   ^=   |=   **=
Assignment operators

Expressions result in sensible types, considering both the types and the values of the operands. For example, 10/2 returns the integer 5 but 5/2 produces the floating point value 2.5. Also, the integer 1, the floating point value 1.0 and the string "1" all compare equal.


File System Tests

The operand of a file system test is interpreted as a word, not an expression, and may involve wildcarding. If wildcarding produces more than one match, the test is done on the first one.

Prefix Operator
True if
-A Archive Bit Set
-C File or Directory is Compressed
-D   -d Directory
-H Hidden File or Directory
-R Read-only File or Directory
-S System File or Directory
-e File or Directory Exists
-f Ordinary File
-o Ownership (Same as Existence on an OS/2 or NT FAT file system)
-r Readable (Same as ordinary file on an OS/2 or NT FAT file system)
-w Writable (Not Read-only and not a directory)
-x Executable (Has a .csh, .exe, .com or .cmd extension and, if it's an .exe or a .com file, appears to be a valid OS/2 or NT binary executable.)
-z Zero-length File

Example:

if (-d $a) then
   echo $a is a directory
end



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