lf/docstring.go

// DO NOT EDIT! (AUTO-GENERATED)

package main

var genDocString = `
lf is a terminal file manager.

Source code can be found in the repository at
https://github.com/gokcehan/lf.

This documentation can either be read from terminal using "lf -doc" or
online at https://godoc.org/github.com/gokcehan/lf.


Reference

The following commands are provided by lf with default keybindings:

    up                (default "k" and "<up>")
    half-up           (default "<c-u>")
    page-up           (default "<c-b>")
    down              (default "j" and "<down>")
    half-down         (default "<c-d>")
    page-down         (default "<c-f>")
    updir             (default "h" and "<left>")
    open              (default "l" and "<right>")
    quit              (default "q")
    bot               (default "G")
    top               (default "gg")
    read              (default ":")
    read-shell        (default "$")
    read-shell-wait   (default "!")
    read-shell-async  (default "&")
    search            (default "/")
    search-back       (default "?")
    search-next       (default "n")
    search-prev       (default "N")
    toggle            (default "<space>")
    invert            (default "v")
    yank              (default "y")
    clear             (default "c")
    delete            (default "d")
    put               (default "p")
    renew             (default "<c-l>")

The following commands are provided by lf without default keybindings:

    sync  synchronizes yanked/deleted files with server
    echo  prints its arguments to the message line
    cd    changes working directory to its argument
    push  simulate key pushes given in its argument

The following options can be used to customize the behavior of lf:

    dirfirst   bool    (default on)
    hidden     bool    (default off)
    preview    bool    (default on)
    reverse    bool    (default off)
    scrolloff  int     (default 0)
    tabstop    int     (default 8)
    filesep    string  (default ":")
    ifs        string  (default "") (not exported if empty)
    previewer  string  (default "") (not filtered if empty)
    shell      string  (default "/bin/sh")
    sortby     string  (default "natural")
    timefmt    string  (default "Mon Jan _2 15:04:05 2006")
    ratios     string  (default "1:2:3")
    info       string  (default "")

The following variables are exported for shell commands:

    $f   current file
    $fs  marked file(s) separated with ':'
    $fx  current file or marked file(s) if any
    $id  id number of the client


Configuration

The configuration file should be located at:

    $XDG_CONFIG_HOME/lf/lfrc"

If "$XDG_CONFIG_HOME" is not set, it defaults to "$HOME/.config" so the
location should be:

    ~/.config/lf/lfrc

A sample configuration file can be found at
https://github.com/gokcehan/lf/blob/master/etc/lfrc.example.


Prefixes

The following command prefixes are used by lf:

    :  read (default)    built-in command
    $  read-shell        shell command
    !  read-shell-wait   shell command waiting for key press
    &  read-shell-async  asynchronous shell command
    /  search            search file in current directory
    ?  search-back       search file in the reverse order

The same evaluator is used for the command line and the configuration file.
The difference is that prefixes are not necessary in the command line.
Instead different modes are provided to read corresponding commands. Note
that by default these modes are mapped to the prefix keys above.


Syntax

Characters from "#" to "\n" are comments and ignored:

    # comments start with '#'

There are three special commands for configuration.

"set" is used to set an option which could be boolean, integer, or string:

    set hidden        # boolean on
    set nohidden      # boolean off
    set hidden!       # boolean toggle
    set scrolloff 10  # integer value
    set sortby time   # string value w/o quotes

"map" is used to bind a key to a command which could be built-in command,
custom command, or shell command:

    map gh cd ~       # built-in command
    map D trash       # custom command
    map i $less "$f"  # shell command
    map u !du -h .    # waiting shell command

You can delete an existing binding by leaving the expression empty:

    map gh            # deletes 'gh' mapping

"cmd" is used to define a custom command

    cmd usage $du -h . | less

You can delete an existing command by leaving the expression empty:

    cmd trash         # deletes trash command

If there is no prefix then ":" is assumed:

    map zt set info time

An explicit ":" could be provided to group statements until a "\n" occurs
which is especially useful for "map" and "cmd" commands:

    map st :set sortby time; set info time

If you need multiline you can wrap statements in "{{" and "}}" after the
proper prefix.

    map st :{{
    	set sortby time
    	set info time
    }}


Mappings

The usual way to map a key sequence is to assign it to a named or unnamed
command. While this provides a clean way to remap builtin keys as well as
other commands, it can be limiting at times. For this reason "push" command
is provided by lf. This command is used to simulate key pushes given as its
arguments. You can "map" a key to a "push" command with an argument to
create various keybindings.

This is mainly useful for two purposes. First, it can be used to map a
command with a command count:

    map <c-j> push 10j

Second, it can be used to avoid typing the name when a command takes
arguments:

    map r push :rename<space>

One thing to be careful is that since "push" command works with keys instead
of commands it is possible to accidentally create recursive bindings:

    map j push 2j

These types of bindings create a deadlock when executed.


Commands

For demonstration let us write a shell command to move selected file(s) to
trash.

A first attempt to write such a command may look like this:

    cmd trash ${{
    	mkdir -p ~/.trash
    	if [ -z $fs ]; then
    		mv --backup=numbered "$f" $HOME/.trash
    	else
    		IFS=':'; mv --backup=numbered $fs $HOME/.trash
    	fi
    }}

We check "$fs" to see if there are any marked files. Otherwise we just
delete the current file. Since this is such a common pattern, a separate
"$fx" variable is provided. We can use this variable to get rid of the
conditional:

    cmd trash ${{
    	mkdir -p ~/.trash
    	IFS=':'; mv --backup=numbered $fx $HOME/.trash
    }}

The trash directory is checked each time the command is executed. We can
move it outside of the command so it would only run once at startup:

    ${{ mkdir -p ~/.trash }}

    cmd trash ${{ IFS=':'; mv --backup=numbered $fx $HOME/.trash }}

Since these are one liners, we can drop "{{" and "}}":

    $mkdir -p ~/.trash

    cmd trash $IFS=':'; mv --backup=numbered $fx $HOME/.trash

Finally note that we set "IFS" variable accordingly in the command. Instead
we could use the "ifs" option to set it for all commands (e.g. "set ifs
':'"). This could be especially useful for interactive use (e.g. "rm $fs"
would simply work). This option is not set by default as things may behave
unexpectedly at other places.


Remote Commands

One of the more advanced features in lf is remote commands. All clients
connect to a server on startup. It is possible to send commands to all or
any of the connected clients over the common server. This is used internally
to notify file selection changes to other clients.

To use this feature, you need to use a client which supports communicating
with a UNIX-domain socket. OpenBSD implementation of netcat (nc) is one such
example. You can use it to send a command to the socket file:

    echo 'send echo hello world' | nc -U /tmp/lf.${USER}.sock

Since such a client may not be available everwhere, lf comes bundled with a
command line flag to be used as such. When using lf, you do not need to
specify the address of the socket file. This is the recommended way of using
remote commands since it is shorter and immune to socket file address
changes:

    lf -remote 'send echo hello world'

In this command "send" is used to send the rest of the string as a command
to all connected clients. You can optionally give it an id number to send a
command to a single client:

    lf -remote 'send 1000 echo hello world'

All clients have a unique id number but you may not be aware of the id
number when you are writing a command. For this purpose, an "$id" variable
is exported to the environment for shell commands. You can use it to send a
remote command from a client to the server which in return sends a command
back to itself. So now you can display a message in the current client by
calling the following in a shell command:

    lf -remote "send $id echo hello world"

A common use for this feature is to display an error message back in the
client. You can implement a safe rename command which does not overwrite an
existing file or directory as such:

    cmd rename ${{
    	if [ -e "$1" ]; then
    		lf -remote "send $id echo file exists"
    	else
    		mv "$f" "$1"
    	fi
    }}

Since lf does not have control flow syntax, remote commands are used for
such needs. Following example can be used to dynamically set the number of
columns on startup based on terminal width:

    ${{
    	w=$(tput cols)
    	if [ $w -le 80 ]; then
    		lf -remote "send $id set ratios 1:2"
    	elif [ $w -le 160 ]; then
    		lf -remote "send $id set ratios 1:2:3"
    	else
    		lf -remote "send $id set ratios 1:2:3:4"
    	fi
    }}

Besides "send" command, there are also two commands to get or set the
current file selection. Two possible modes "copy" and "move" specify whether
selected files are to be copied or moved. File names are separated ":"
character. Setting the file selection is done with "save" command:

    lf -remote 'save copy foo.txt:bar.txt:baz.txt'

Getting the file selection is similarly done with "load" command. You may
need to parse the response as such to achieve what you need:

    resp=$(lf -remote 'load')
    mode=$(echo $resp | cut -d' ' -f1)
    list=$(echo $resp | cut -d' ' -f2-)
    if [ $mode == 'copy' ]; then
    	# do something with the $list
    elif [ $mode == 'move' ]; then
    	# do something else with the $list
    fi

Lastly, there is a "conn" command to connect the server as a client. This
should not be needed for users.


File Operations

lf uses the underlying "cp" and "mv" shell commands for file operations. For
this purpose, when you "yank" (i.e. copy) a file, it doesn't actually copy
the file on the disk, but only records its name to memory. The actual file
operation takes place when you do the "put" in which case the "cp" command
is used. Similarly the "mv" command is used for "delete" (i.e. cut or kill)
followed by "put". These traditional names (e.g. "yank", "delete", and
"put") are picked instead of the other common convention (e.g. copy and cut)
to resemble the default keybinds for these operations.

By default, lf does not provide an actual file deletion command to protect
new users. You can define such a command and optionally assign a key if you
like. An example command to move selected files to a trash folder and remove
files completely are provided in the example configuration file.


Opening Files

You can use "open-file" command to open a file. This is a special command
called by "open" when the current file is not a directory. Normally a user
maps the "open" command to a key (default "l") and customize "open-file"
command as desired. You can define it just as you would define any other
command:

    cmd open-file $IFS=':'; vim $fx

It is possible to use different command types:

    cmd open-file &xdg-open "$f"

You may want to use either file extensions or mime types from "file"
command:

    cmd open-file ${{
    	case $(file --mime-type "$f" -b) in
    		text/*) IFS=':'; vim $fx;;
    		*) IFS=':'; for f in $fx; do xdg-open "$f" > /dev/null 2> /dev/null & done;;
    	esac
    }}

lf does not come bundled with a file opener. You can use any of the existing
file openers as you like. Possible options are "open" (for Mac OS X only),
"xdg-utils" (executable name is "xdg-open"), "libfile-mimeinfo-perl"
(executable name is "mimeopen"), "rifle" (ranger's default file opener), or
"mimeo" to name a few.


Previewing Files

lf previews files on the preview pane by printing the file until the end or
the preview pane is filled. This output can be enhanced by providing a
custom preview script for filtering. This can be used to highlight source
codes, list contents of archive files or view pdf or image files as text to
name few. For coloring lf recognizes ansi escape codes.

In order to use this feature you need to set the value of "previewer" option
to the path of an executable file. lf passes the current file name as the
first argument and the height of the preview pane as the second argument
when running this file. Output of the execution is printed in the preview
pane. You may want to use the same script in your pager mapping as well if
any:

    set previewer ~/.config/lf/pv.sh
    map i $~/.config/lf/pv.sh "$f" | less -R

Since this script is called for each file selection change it needs to be as
efficient as possible and this responsibility is left to the user. You may
use file extensions to determine the type of file more efficiently compared
to obtaining mime types from "file" command. Extensions can then be used to
match cleanly within a conditional:

    #!/bin/sh

    case "$1" in
    	*.tar*) tar tf "$1";;
    	*.zip) unzip -l "$1";;
    	*.rar) unrar l "$1";;
    	*.7z) 7z l "$1";;
    	*.pdf) pdftotext "$1" -;;
    	*) highlight -O ansi "$1" || cat "$1";;
    esac

Another important consideration for efficiency is the use of programs with
short startup times for preview. For this reason, "highlight" is recommended
over "pygmentize" for syntax highlighting. Besides, it is also important
that the application is processing the file on the fly rather than first
reading it to the memory and then do the processing afterwards. This is
especially relevant for big files. lf automatically closes the previewer
script output pipe with a SIGPIPE when enough lines are read. When
everything else fails, you can make use of the height argument to only feed
the first portion of the file to a program for preview.
`