Built into the TC shell are several variables consisting of one character. The $ preceding the character allows variable interpretation. See Table 10.21.
|$?var||echo $?name||Returns 1 if variable has been set, 0 if not.|
|$#var||echo $#fruit||Prints the number of elements in an array.|
|$%var||echo $%name||Prints number of characters in a variable or array.|
|$$||echo $$||Prints the PID of the current shell.|
|$<||set name = $<||Accepts a line of input from user up to newline.|
|$?||echo $?||Same as $status. Contains the exit status of the last command.|
|$!||kill $!||Contains the process id number of the last job put in the background.|