Line editing in MIDAS

MIDAS is provided with two different line editors TermWindows and GNU readline.
TermWindows was developed at ESO and has been until 94MAY the line editor used by the MIDAS monitor. However, starting with 94NOV the line editor by default is now the GNU readline but the TermWindows is still available the user environment variable TERMWIN is set to yes.

The GNU readline is a public domain library widely supported on many UNIX platforms and enhances the line-editor capabilities of MIDAS like a history stack of commands, Emacs or Vi editing mode, command and filename completion functions and a communication channel with the MIDAS Graphical User Interface HELP for help-on-line functions.

The editing mode by default with GNU readline is Emacs but it can be switched to mode Vi by setting the variable editing-mode to vi in the initialization file $INPUTRC if exists otherwise in the file $HOME/.inputrc. As a brief introduction to GNU readline here is list of most common key-sequences:

   Self-insert                 CTR-L  -> clear-screen
   CTR-E -> end-of-line        CTR-A  -> beginning-of-line
   CTR-U -> unix-line-discard  CTR-K  -> kill-line
   TAB   -> complete           TABs   -> possible-completions
   CTR-X -> (also F1) on-line-help through the GUI HELP

More detailed information about editing commands with GNU readline in the man-page /midas/98NOV/system/unix/readline.l