tar tar_options file
the first call to this function resets the function definition accordingly so that the next call calls the new function and there is no need for check every time the function is called. use $TAR as a command if set or also check for tar and set $TAR and make $TAR readonly for future calls. The first call without any arguments, serves to check for existence of tar, searched in the order of preference of TAR, tar-1.13 and tar(replacement for earlier tar -c). If you want to call the normal command tar, use command tar (replacement for tar -t)