Here you can find a list of keyboard shortcuts you can use when you connect a wireless bluetooth keyboard or a keyboard dock to your iPad. These shortcuts work in all iOS apps.
Keyboard shortcuts supported by iOS / iPad:
• Cmd+A - Select All
• Cmd+C - Copy
• Cmd+X - Cut
• Cmd+V - Paste
• Cmd+Z - Undo
• Cmd+Shift+Z - Redo
• Shift+Arrow - Select text
• Cmd+Up/Down - Move cursor to the beginning/end of the file
• Cmd+Left/Right - Move cursor to beginning/end of the current line
• Alt+Left/Right - Move cursor to the previous/next word
• Esc - Bring up virtual on-screen keyboard
• Alt-Delete - Delete the word to the left of the cursor
• Cmd-Delete - Delete everything on the current line to the left of the cursor
iOS also supports these Emacs keybindings:
• Ctrl-A - Move cursor to the beginning of the line
• Ctrl-E - Move cursor to the end of the line
• Ctrl-F - Move cursor forward one character
• Ctrl-B - Move cursor backward one character
• Ctrl-K - Kill/delete text between cursor and the end of the line
• Ctrl-H - Delete one character to the left
Textastic also supports these special shortcuts:
• Tab - Indent selected text
• Shift-Tab - Unindent selected text
Note: Unfortunately, the standard shortcuts are entirely provided by the iOS operating system and there's no way for third party developers to extend them with custom shortcuts that use modifier keys like Ctrl, Cmd or Alt.