Command interfaces

Advantages:

• Hands remain on the keyboard
• Fast input
• Powerful language constructs possible ("print file1 file2 file3", wildcards, pipes, ...)

Disadvantages:

• Difficult to learn
• Difficult to retain

Guidelines:

• Use action-oriented command names that come in the first place, i.e. <command> <arg1> <arg2>...
  (e.g., "move a b" rather than "a move b" or "location a b")
• Use congruent names for antagonistic commands (Carroll 1982)
• Use consistent order of arguments
• Specifiy direct object in first argument (Barnard et al., 1982)
• Allow natural/consistent abbreviations for command names
  (e.g., "mv" for "move"; cf. Shneiderman 1998)
• Allow for variations in the syntax; tolerate spurious words (e.g., "mv a to b")
• Allow for the definition of aliases
• Provide command history
• Allow for the editing and re-entry of the last few commands
• If possible, allow multiple parameters and wildcards
• If possible, allow macro definition and programming