Editing COMMAND.COM (section)

==Variables==
Batch files for COMMAND.COM can have four kinds of variables:
* [[Environment variable]]s: These have the {{mono|%VARIABLE%}} form and are associated with values with the SET statement. Before DOS 3 COMMAND.COM will only expand environment variables in batch mode; that is, not interactively at the command prompt.{{citation needed|date=August 2017}}
* [[Replacement parameter]]s: These have the form {{mono|%0}}, {{mono|%1}}...{{mono|%9}}, and initially contain the command name and the first nine [[command-line parameter]]s passed to the script (e.g., if the invoking command was {{kbd|myscript.bat John Doe}}, then {{mono|%0}} is "myscript.bat", {{mono|%1}} is "John" and {{mono|%2}} is "Doe").  The parameters to the right of the ninth can be mapped into range by using the SHIFT statement.{{Citation needed|date=March 2024}}
* Loop variables: Used in loops, they have the {{mono|%%a}} format when run in batch files. These variables are defined solely within a specific FOR statement, and iterate over a certain set of values defined in that FOR statement.{{Citation needed|date=March 2024}}
* Under [[Novell DOS 7]]<!-- 1993 -->, [[OpenDOS 7.01]], [[DR-DOS 7.02]] and higher, COMMAND.COM also supports a number of [[system information variable]]s,<ref name="Caldera_1998_USER_CH7"/><ref name="Caldera_1998_USER"/><ref name="Paul_1997_NWDOSTIP"/> a feature earlier found in [[4DOS 3.00]]<!-- 1990 --> and higher<ref name="4DOS_8.00_HELP"/> as well as in [[Multiuser DOS]],<!-- 1991 --><ref name="Paul_1997_NWDOSTIP"/><!-- not in CDOS 386 1.0 (1987), not sure about CDOS 386 3.0 (1989) --> although most of the supported variable names differ.