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ENVIRON Statement Details
 
Syntax
  ENVIRON stringexpression
 
The stringexpression must be of the form
  parameterid=text
or the form
  parameterid text
 
Everything to the left of the equal sign or space is assumed to be a
parameter, and everything to the right, text.
 
If the parameterid has not previously existed in the environment-
string table, it is appended to the end of the table. If a parameterid
exists in the table when the ENVIRON statement is executed, it is
deleted and the new parameterid is appended to the end of the table.
 
The text string is the new parameter text. If the text is a null
string ("") or a semi-colon (";"), then the existing parameter
is removed from the environment-string table and the remaining body
of the table is compressed.
 
DOS discards the environment-string table modified by this function
when your program ends. The environment-string table is the same as
it was before your program ran.
 
You may use this statement to change the PATH parameter for a "child"
process (a program or command started by a SHELL statement) or to
pass parameters to a child by inventing a new environment parameter.
 
Errors in environment-string tables include parameters that are not
strings and lack of free space. An Out of memory error message
is printed when no more space can be allocated to the environment-
string table. The amount of free space in the table is usually quite
small.