MLE(1)

NAME
mle - flexible terminal-based text editor

SYNOPSIS
mle [-abceHhiKklMmNnpSstuvwxyz] [file[:line]] ...

DESCRIPTION
mle is a small, flexible, terminal-based text editor written in C. It runs on Linux, Windows (Cygwin or WSL), FreeBSD, macOS, and more.

  Basic usage

      $ mle             # Open blank buffer
      $ mle one.c       # Edit one.c
      $ mle one.c:100   # Edit one.c at line 100
      $ mle one.c two.c # Edit one.c and two.c
      $ mle -h          # Show command line help

The default key bindings are intuitive. Input text as normal, use directional keys to move around, use `Ctrl-S` to save, `Ctrl-O` to open, `Ctrl-X` to exit.

Press `F2` for full help.

  Options

-h  Show help

-a <1|0>
    Enable/disable tab to space (default: 1)

-b <1|0>
    Enable/disable highlight bracket pairs (default: 1)

-c column
    Color column (default: -1, disabled)

-e <1|0>
    Enable/disable mouse support (default: 0)

-H <1|0>
    Enable/disable headless mode (default: 1 if no tty, else 0)

-i <1|0>
    Enable/disable auto indent (default: 0)

-K kdef
    Make a kmap definition (use with -k).

    kdef is formatted as `<name>,<default_cmd>,<allow_fallthru>`, where name is the name of the kmap, default_cmd is the default command handler (can be empty), and allow_fallthru is a 0 or 1 specifying whether unhandled key input should be forwarded to the previous kmap on the stack or not.

-k kbind
    Add key binding to current kmap definition (use after -K).

    kbind is formatted as `<cmd>,<key>,<param>`, where cmd is a command name, key is a key name, and param is a static parameter passed to the command (can be empty).

-l ltype
    Set linenum type (default: 0, absolute).

    ltype can be 0 (absolute), 1 (relative), or 2 (both)

-M macro
    Add a macro.

    macro is formatted as `<name> <key1> <key2> ... <keyN>`, where name is the name of the macro, and keyN are space-separated key names.

-m key
    Set macro toggle key (default: M-r). key is a key name.

-N  Skip reading of rc file

-n kmap
    Set init kmap (default: mle_normal). kmap is a kmap name.

-p macro
    Set startup macro. macro is a macro name.

-S syndef
    Make a syntax definition (use with -s).

    syndef is formatted as `<name>,<path_pattern>,<tab_width>,<tab_to_space>`, where name is a syntax name, path_pattern is a path matching regex (PCRE), tab_width is the default tab width, tab_to_space is a 0 or 1 specifying whether to convert tabs to spaces or not.

-s synrule
    Add syntax rule to current syntax definition (use after -S).

    synrule is formatted as `<start>,<end>,<fg>,<bg>`, where start and end are text matching regexes (PCRE), and fg and bg are attributes to apply to matching text.

    If both start and end are supplied, the rule applies to all text matched in between the regexes, potentially spanning multiple lines. If only start is specified, the rule applies to text matched by the regex on a single line.

    Attributes for fg and bg are as follows:

    0   default

    1   black

    2   red

    4   yellow

    5   blue

    6   magenta

    7   cyan

    8   white

    256 bold

    512 underline

    1024
        reverse

    2048
        italic

-t size
    Set tab size (default: 4)

-u <1|0>
    Enable/disable coarse undo/redo (default: 0)

-v  Print version and exit

-w <1|0>
    Enable/disable soft word wrap (default: 0)

-x uscript
    Run a Lua user script (experimental)

-y syntax
    Set override syntax for files opened at start up. If '-' is specified, use the built-in generic syntax. syntax is any syntax name.

-z <1|0>
    Enable/disable trimmed paste (default: 1)

KEY NAMES
Key names for -k, -M, and -m are formatted as `<key>` or `<mod>-<key>`.

key is any character or one of the following: space, tab, enter, backspace, comma, up, down, left, right, insert, delete, home, end, pgup, pgdn, backtab, f1, f2, f3, f4, f5, f6, f7, f8, f9, f10, f11, f12.

mod is one of

S   Shift

M   Alt (Meta)

MS  Alt-Shift

C   Ctrl

CS  Ctrl-Shift

CM  Ctrl-Alt

CMS Ctrl-Alt-Shift

Not all key names are valid or supported by all terminals. Run with `-Qk` to display key names for given input.

ADVANCED USAGE
Below are some advanced things you can do with mle.

  rc file
To customize the editor, make an rc file named ~/.mlerc or /etc/mlerc. The contents of the rc file are any number of cli options separated by newlines. Lines that begin with a semi-colon are interpreted as comments.

If the rc file is executable, mle executes it and interprets the resulting stdout as described above. For example, consider the following snippet from an executable ~/.mlerc bash(1) script:

      ...
      # Define 'test' kmap
      echo '-Ktest,,1'
      # M-q: replace grep with git grep if `.git` exists
      if [ -d ".git" ]; then
        echo '-kcmd_grep,M-q,git grep --color=never -P -i -I -n %s 2>/dev/null'
      fi
      # Set default kmap
      echo '-n test'
      ...

This overrides the built-in grep command with `git grep` if .git exists in the current working directory.

  Shell command integration
The following programs will enable or enhance certain features of mle if they exist in PATH.

bash(1)
    file tab completion

fzf(1)
    fuzzy file search

grep(1)
    file grep

less(1)
    less integration

perl(1)
    perl 1-liners

readtags(1)
    ctags integration

tree(1)
    file browsing

Arbitrary shell commands can also be run via `cmd_shell` (M-e by default). If any text is selected, it is sent to stdin of the command. Any resulting stdout is inserted into the text buffer.

  Headless mode
mle provides support for non-interactive editing which may be useful for using the editor as a regular command line tool. In headless mode, mle reads stdin into a buffer, applies a startup macro if specified, and then writes the buffer contents to stdout. For example:

      $ echo -n hello | mle -M 'test C-e space w o r l d enter' -p test
      hello world

If stdin is a pipe, mle goes into headless mode automatically. Headless mode can be explicitly enabled or disabled with the `-H` option.

If stdin is a pipe and headless mode is disabled via -H0, mle reads stdin into a new buffer and then runs as normal in interactive mode.

  Scripting (experimental)
mle is extensible via the Lua programming language. Scripts are loaded via the `-x` cli option. Commands registered by scripts can be mapped to keys as normal via `-k`. See https://github.com/adsr/mle for more info.

ACKNOWLEDGEMENTS
mle makes extensive use of the following libraries.

uthash
    for hash maps and linked lists

termbox2
    for TUI

PCRE2
    for syntax highlighting and search