TMPDIR

codice_1 is the canonical environment variable in Unix and POSIX that should be used to specify a temporary directory for scratch space. Most Unix programs will honor this setting and use its value to denote the scratch area for temporary files instead of the common default of or .
Other forms sometimes accepted are codice_2, codice_3 and codice_4, but these alternatives are used more commonly by non-POSIX operating systems or non-conformant programs.
codice_1 is specified in various Unix and similar standards, e.g. per the Single UNIX Specification.