1GENERAL: intrinsics - intrinsic functions of the command interpreter

The following functions can be used in FORTRAN-77 expressions in addition 
to the standard FORTRAN-77 intrinsic functions or anywhere on the command
line in the form $<function>(<parameter>,<parameter>,...) if there are
parameters or in the form $<function> without parameters. In the alpha-
betical list below, s denotes a character expression. 
 
function  result   description
--------  -------  ------------------------------------------------------
def(s)    logical  does a variable with name s exist and have a value
                   different from NULL?
exist(s)  logical  does a variable with name s exist?
file(s)   logical  does a file with name s exist?
length(s) integer  number of elements of the variable with name s
lenstr(s) integer  length of string s (without trailing blanks)
macro(s)  logical  is a macro with name s in the search path?
opened(s) logical  is the file with name s open?

See also: functions