system cmdstr1 ?cmdstr2...? Concatenates cmdstr1, cmdstr2 etc with space sep- arators (see the concat command) into a single com- mand and then evaluates the command using the stan- dard system shell. On Unix systems, this is /bin/sh and om Windows its command.com. The exit code of the command is returned. This command differs from the exec command in that system doesn't return the executed command's stan- dard output as the result string, and system goes through the Unix shell to provide wildcard expan- sion, redirection, etc, as is normal from an sh command line. This command is provided by Extended Tcl.