Editing COMMAND.COM (section)

==== IF command ====
On exit, all external commands submit a [[return code]] (a value between 0 and 255) to the calling program. Most programs have a certain convention for their return codes (for instance, 0 for a successful execution).<ref name="Paul_1997_BATTIPS"/><ref name="FD_2003_Errorlevel"/><ref name="Paul_2003_Exitcodes"/><ref name="Allen_2005"/>

If a program was invoked by COMMAND.COM, the internal IF command with its ERRORLEVEL conditional can be used to test on error conditions of the last invoked external program.{{Citation needed|date=March 2024}}

Under COMMAND.COM, internal commands do not establish a new value.{{Citation needed|date=March 2024}}