eh(1)

Name

eh - Edit Here - vi(1) the good parts version

Synopsis

eh [filename]

Description

A minimalist version of vi(1). It is an example of the "Buffer Gap" method outlined in the The Craft Of Text Editing used by many Emacs style editors. (Yep I mixed vi and emacs in the same paragraph; I'm going to hell for that one.)

Create or read a text file to edit. Text files consists of lines of printable UTF-8 text, tabs, or newline characters. A physical line can be of arbitrary length and is delimited by either a newline or the end of file. Tab stops are every eight columns. The behaviour of non-printable characters may vary depending on the implementation of the Curses library, stty(1) settings, or terminal emulator.

Commands

The commands are similar, but not the same as vi(1). Most commands can be prefixed by a repeat count, eg. 5w, 123G, 2dw (d2w), or 2d3w (d6w). Motion commands, optionally prefixed by a count, are those that move the cursor without modifying the buffer. Some edit commands can be followed by a motion.

• h j k l Left, down, up, right cursor movement.
• H J K L Page top, page down, page up, page bottom.
• ^F ^B Page down (forward), page up (back).
• b e w Word left, word end, word right.
• ^ $ Start and end of line, ie. 0| or 999|.
• | Goto column (count) of physical line.
• % * Find matching brace, bracket, square bracket, or angle bracket.
• /ERE /ERE/ Find first occurrence of ERE pattern after the cursor.
• /ERE/REPL /ERE/REPL/ Find ERE and replace. In the REPL, a $n where n is a digit 0..9 is replaced by the Nth subexpression of the matched text; $0 is the whole matched text. \x is an escape sequence, ie. \a \b \e \f \n \r \t \? or x.
• /ERE/REPL/a Find and replace all occurences.
• m char Set a positional mark letter a..z.
• n Find next occurrence of ERE (and replace); u undoes only the most recent replacement.
• ` char Goto position of mark `a .. `z or `` (previous).
• ' char * Goto start of line with mark 'a .. 'z or '' (previous), eg. `a^.
• G Goto line (count) number; 1G top of file, G bottom, 123G line 123.
• \ Toggle highlighted text selection.
• c move Change text selection or region given by motion.
• C * Change to end of line, ie. c$.
• d move Delete text selection or region given by motion.
• D * Delete to end of line, ie. d$.
• O o * Open new line above or below the current line, ie. kA\n or A\n.
• y move Yank (copy) text selection or region given by motion.
• Y * Yank the current line, ie. ^yj.
• P p Paste last deleted or yanked text region before or after the cursor.
• i a Insert text mode before or after the cursor, ESC or CTRL+C ends insert. While inserting text, backspace will erase the previous character; CTRL+V treats the next character as a literal character.
• I A * Insert at start of line or append at end of line, ie. ^i or $i.
• X x Delete character before or after cursor, ie. dh or dl.
• U u Redo or undo one or more edits.
• ~ Invert character case.
• ! move cmd Filter a text selection or region through shell command line, eg. !Gfmt -w68. Or read only the output of a shell command line, eg. !!ls -l.
• CTRL+X Toggle hex digits in the range 0..10FFFF or a Unicode character left of the cursor.
• R Read a file into buffer after cursor.
• W Write buffer to file.
• V Show build and version.
• Q Quit.
• CTRL+C Quit.
• Any other key will redraw the screen.

Environment

• SHELL : The user's shell of choice.

• TERM : The user's terminal type. If the environmental variable TERM is not set or insufficient then terminate with non-zero exit status.

• TERMINFO : The absolute file path of a terminfo database. See terminfo(5).

Exit Status

• 0 Success
• 1 Insufficient capabilities for TERM.
• 2 Read file error

See Also

ed(1), ex(1), vi(1)

Notes

• Has UTF-8 support.

  • Loads UTF-8 files as-is and internally remains UTF-8 (not converteed to wchar_t or char32_t).
  • UTF-8 input will likely require an intl. keyboard or enabling US Intl. dead-key keyboard support. See also Unicode Input.

• The display of long physical lines that are larger than the terminal screen is untested, so considered undefined.

• Control characters, other than TAB and LF, are displayed as highlighted alphabetic characters.

• u and U do not behave as in historical vi(1); they now provide multi undo and redo respectively.

• CRLF newlines (DOS, Windows) should be converted to LF newlines Consider converting newlines using SUS tools like awk(1) or sed(1):

    $ sed -e's/^V^M$//' dos.txt > unix.txt
    $ sed -e's/$/^V^M/' unix.txt > dos.txt
  

  ^V is the default stty(1) insert literal prefix key.

• Cygwin builds may be bugged with respect to wcwidth(), since wchar_t reflects UTF-16 to match Windows and there is no equivalent c32width() nor means to determine cell width of surrogate pairs, such as emoji.

References

• Craig A. Finseth, "Craft Of Text Editing", 1991
  Springer-Verlag, ISBN 0-387-97616-7, ISBN 3-3540-97616-7

• Craig A. Finseth, "Craft Of Text Editing", 1999
  http://www.finseth.com/craft/

• Webb Miller, "A Software Tools Sampler", Prentice Hall, 1987
  ISBN 0-13-822305-X, chapter 5

• Single Unix Specification, Base Specification 2018, vi(1)
  https://pubs.opengroup.org/onlinepubs/9699919799/utilities/vi.html

• Single Unix Specification, Curses issue 7
  https://pubs.opengroup.org/onlinepubs/9699909599/toc.pdf