lf: github.com/gokcehan/lf Files

Command lf

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. You can also use 'doc' command (default '<f-1>') inside lf to view the documentation in a pager.

You can run 'lf -help' to see descriptions of command line options.

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>' and '<pgup>')
down                  (default 'j' and '<down>')
half-down             (default '<c-d>')
page-down             (default '<c-f>' and '<pgdn>')
updir                 (default 'h' and '<left>')
open                  (default 'l' and '<right>')
quit                  (default 'q')
top                   (default 'gg' and '<home>')
bottom                (default 'G' and '<end>')
toggle                (default '<space>')
invert                (default 'v')
unselect              (default 'u')
copy                  (default 'y')
cut                   (default 'd')
paste                 (default 'p')
clear                 (default 'c')
redraw                (default '<c-l>')
reload                (default '<c-r>')
read                  (default ':')
shell                 (default '$')
shell-pipe            (default '%')
shell-wait            (default '!')
shell-async           (default '&')
find                  (default 'f')
find-back             (default 'F')
find-next             (default ';')
find-prev             (default ',')
search                (default '/')
search-back           (default '?')
search-next           (default 'n')
search-prev           (default 'N')
mark-save             (default 'm')
mark-load             (default "'")

The following commands are provided by lf without default keybindings:

draw    draw the ui
load    load modified files and directories
sync    synchronizes copied/cut files with server
echo    prints its arguments to the message line
cd      changes working directory to its argument
select  changes current file selection to its argument
source  reads the configuration file in its argument
push    simulate key pushes given in its argument

The following command line commands are provided by lf with default keybindings:

cmd-escape            (default '<esc>')
cmd-complete          (default '<tab>')
cmd-enter             (default '<c-j>' and '<enter>')
cmd-history-next      (default '<c-n>')
cmd-history-prev      (default '<c-p>')
cmd-delete            (default '<c-d>' and '<delete>')
cmd-delete-back       (default '<bs>' and '<bs2>')
cmd-left              (default '<c-b>' and '<left>')
cmd-right             (default '<c-f>' and '<right>')
cmd-home              (default '<c-a>' and '<home>')
cmd-end               (default '<c-e>' and '<end>')
cmd-delete-home       (default '<c-u>')
cmd-delete-end        (default '<c-k>')
cmd-delete-unix-word  (default '<c-w>')
cmd-yank              (default '<c-y>')
cmd-transpose         (default '<c-t>')
cmd-interrupt         (default '<c-c>')
cmd-word              (default '<a-f>')
cmd-word-back         (default '<a-b>')
cmd-capitalize-word   (default '<a-c>')
cmd-delete-word       (default '<a-d>')
cmd-uppercase-word    (default '<a-u>')
cmd-lowercase-word    (default '<a-l>')
cmd-transpose-word    (default '<a-t>')

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

anchorfind  boolean   (default on)
dircounts   boolean   (default off)
dirfirst    boolean   (default on)
drawbox     boolean   (default off)
globsearch  boolean   (default off)
hidden      boolean   (default off)
ignorecase  boolean   (default on)
ignoredia   boolean   (default off) (ignore diacritics in latin letters for search and find)
incsearch   boolean   (default off)
preview     boolean   (default on)
reverse     boolean   (default off)
smartcase   boolean   (default on)
smartdia    boolean   (default off)
wrapscan    boolean   (default on)
findlen     integer   (default 1) (zero to prompt until single match)
period      integer   (default 0) (zero to disable periodic loading)
scrolloff   integer   (default 0)
tabstop     integer   (default 8)
filesep     string    (default "\n")
ifs         string    (default '') (not exported if empty)
previewer   string    (default '') (not filtered if empty)
promptfmt   string    (default "\033[32;1m%u@%h\033[0m:\033[34;1m%w/\033[0m\033[1m%f\033[0m")
shell       string    (default 'sh')
sortby      string    (default 'natural')
timefmt     string    (default 'Mon Jan _2 15:04:05 2006')
ratios      string    (default '1:2:3')
info        string    (default '')
shellopts   string    (default '')

The following variables are exported for shell commands:

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

The following variables are set to the corresponding values:

$LF_LEVEL  current nesting level

The following default values are set to the environmental variables on unix when they are not set or empty:

$OPENER  open      # macos
$OPENER  xdg-open  # others
$EDITOR  vi
$PAGER   less
$SHELL   sh

The following default values are set to the environmental variables on windows when they are not set or empty:

%OPENER%  start
%EDITOR%  notepad
%PAGER%   more
%SHELL%   cmd

The following additional keybindings are provided by default:

map zh set hidden!
map zr set reverse!
map zn set info
map zs set info size
map zt set info time
map za set info size:time
map sn :set sortby natural; set info
map ss :set sortby size; set info size
map st :set sortby time; set info time
map gh cd ~

The following keybindings to applications are provided by default:

map e $$EDITOR $f
map i $$PAGER $f
map w $$SHELL

Configuration

Configuration files should be located at:

os       system-wide             user-specific
unix     /etc/lf/lfrc            ~/.config/lf/lfrc
windows  C:\ProgramData\lf\lfrc  C:\Users\<user>\AppData\Local\lf\lfrc

Marks file should be located at:

unix     ~/.local/share/lf/marks
windows  C:\Users\<user>\AppData\Local\lf\marks

History file should be located at:

unix     ~/.local/share/lf/history
windows  C:\Users\<user>\AppData\Local\lf\history

You can configure the default values of following variables to change these locations:

$XDG_CONFIG_HOME  ~/.config
$XDG_DATA_HOME    ~/.local/share
%ProgramData%     C:\ProgramData
%LOCALAPPDATA%    C:\Users\<user>\AppData\Local

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)  builtin/custom command
$  shell           shell command
%  shell-pipe      shell command running with the ui
!  shell-wait      shell command waiting for key press
&  shell-async     shell command running asynchronously
/  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 for read and shell commands. The difference is that prefixes are not necessary in the command line. Instead, different modes are provided to read corresponding commands. These modes are mapped to the prefix keys above by default. Searching commands are only used from the command line.

Syntax

Characters from '#' to newline are comments and ignored:

# comments start with '#'

There are three special commands ('set', 'map', and 'cmd') and their variants for configuration.

Command 'set' is used to set an option which can 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
set sortby 'time'  # string value with single quotes (whitespaces)
set sortby "time"  # string value with double quotes (backslash escapes)

Command 'map' is used to bind a key to a command which can be builtin command, custom command, or shell command:

map gh cd ~        # builtin command
map D trash        # custom command
map i $less $f     # shell command
map U !du -sh      # waiting shell command

Command 'cmap' is used to bind a key to a command line command which can only be one of the builtin commands:

cmap <c-g> cmd-escape

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

map gh             # deletes 'gh' mapping
cmap <c-g>         # deletes '<c-g>' mapping

Command 'cmd' is used to define a custom command:

cmd usage $du -h -d1 | 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 ':' can be provided to group statements until a newline 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
}}

Key Mappings

Regular keys are assigned to a command with the usual syntax:

map a down

Keys combined with the shift key simply use the uppercase letter:

map A down

Special keys are written in between '<' and '>' characters and always use lowercase letters:

map <enter> down

Angle brackets can be assigned with their special names:

map <lt> down
map <gt> down

Function keys are prefixed with 'f' character:

map <f-1> down

Keys combined with the control key are prefixed with 'c' character:

map <c-a> down

Keys combined with the alt key are assigned in two different ways depending on the behavior of your terminal. Older terminals (e.g. xterm) may set the 8th bit of a character when the alt key is pressed. On these terminals, you can use the corresponding byte for the mapping:

map รก down

Newer terminals (e.g. gnome-terminal) may prefix the key with an escape key when the alt key is pressed. lf uses the escape delaying mechanism to recognize alt keys in these terminals (delay is 100ms). On these terminals, keys combined with the alt key are prefixed with 'a' character:

map <a-a> down

Please note that, some key combinations are not possible due to the way terminals work (e.g. control and h combination sends a backspace key instead). The easiest way to find the name of a key combination is to press the key while lf is running and read the name of the key from the unknown mapping error.

Push 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.

Shell Commands

Regular shell commands are the most basic command type that is useful for many purposes. For example, we can 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 "$f" ~/.trash
    else
        IFS="`printf '\n\t'`"; mv $fs ~/.trash
    fi
}}

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

cmd trash ${{
    mkdir -p ~/.trash
    IFS="`printf '\n\t'`"; mv $fx ~/.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="`printf '\n\t'`"; mv $fx ~/.trash }}

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

$mkdir -p ~/.trash

cmd trash $IFS="`printf '\n\t'`"; mv $fx ~/.trash

Finally note that we set 'IFS' variable manually in these commands. Instead we could use the 'ifs' option to set it for all shell commands (i.e. 'set ifs "\n"'). This can be especially useful for interactive use (e.g. '$rm $f' or '$rm $fs' would simply work). This option is not set by default as it can behave unexpectedly for new users. However, use of this option is highly recommended and it is assumed in the rest of the documentation.

Piping Shell Commands

Regular shell commands have some limitations in some cases. When an output or error message is given and the command exits afterwards, the ui is immediately resumed and there is no way to see the message without dropping to shell again. Also, even when there is no output or error, the ui still needs to be paused while the command is running. This can cause flickering on the screen for short commands and similar distractions for longer commands.

Instead of pausing the ui, piping shell commands connects stdin, stdout, and stderr of the command to the statline in the bottom of the ui. This can be useful for programs following the unix philosophy to give no output in the success case, and brief error messages or prompts in other cases.

For example, following rename command prompts for overwrite in the statline if there is an existing file with the given name:

cmd rename %mv -i $f $1

You can also output error messages in the command and it will show up in the statline. For example, an alternative rename command may look like this:

cmd rename %[ -e $1 ] && printf "file exists" || mv $f $1

One thing to be careful is that although input is still line buffered, output and error are byte buffered and verbose commands will be very slow to display.

Waiting Shell Commands

Waiting shell commands are similar to regular shell commands except that they wait for a key press when the command is finished. These can be useful to see the output of a program before the ui is resumed. Waiting shell commands are more appropriate than piping shell commands when the command is verbose and the output is best displayed as multiline.

Asynchronous Shell Commands

Asynchronous shell commands are used to start a command in the background and then resume operation without waiting for the command to finish. Stdin, stdout, and stderr of the command is neither connected to the terminal nor to the ui.

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 everywhere, 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"

Since lf does not have control flow syntax, remote commands are used for such needs. For example, you can configure the number of columns in the ui with respect to the terminal width as follows:

cmd recol %{{
    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 1:2:3:5"
    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 by newline character. Setting the file selection is done with 'save' command:

lf -remote "$(printf 'save\ncopy\nfoo.txt\nbar.txt\nbaz.txt\n')"

Getting the file selection is similarly done with 'load' command:

load=$(lf -remote 'load')
mode=$(echo "$load" | sed -n '1p')
list=$(echo "$load" | sed '1d')
if [ $mode = 'copy' ]; then
    # do something with $list
elif [ $mode = 'move' ]; then
    # do something else with $list
fi

There is a 'quit' command to close client connections and quit the server:

lf -remote 'quit'

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 '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 'paste' in which case the 'cp' command is used. Similarly the 'mv' command is used for 'cut' followed by 'paste'.

You can customize these operations by defining a 'paste' command. This is a special command that is called when it is defined instead of the builtin implementation. The default behavior is similar to the following command:

cmd paste %{{
    load=$(lf -remote 'load')
    mode=$(echo "$load" | sed -n '1p')
    list=$(echo "$load" | sed '1d')
    if [ $mode = 'copy' ]; then
        cp -R -n $list .
    elif [ $mode = 'move' ]; then
        mv -n $list .
    fi
    lf -remote 'send load'
    lf -remote 'send clear'
}}

Some useful things are to use the backup option ('--backup') with 'cp' and 'mv' commands if they support it (i.e. GNU implementation), change the command type to asynchronous, or use 'rsync' command with progress bar option for copying and feed the progress to the client periodically with remote 'echo' calls.

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 define a an 'open' command (default 'l') to configure file opening. This command is only called when the current file is not a directory, otherwise the directory is entered instead. You can define it just as you would define any other command:

cmd open $vi $fx

It is possible to use different command types:

cmd open &xdg-open $f

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

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

Following command is provided by default:

cmd open &$OPENER $f

You may also use any other existing file openers as you like. Possible options are '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.

Colorschemes

lf tries to automatically adapt its colors to the environment. On startup, first '$LS_COLORS' environment variable is checked. This variable is used by GNU ls to configure its colors based on file types and extensions. The value of this variable is often set by GNU dircolors in a shell configuration file. dircolors program itself can be configured with a configuration file. dircolors supports 256 colors along with common attributes such as bold and underline.

If '$LS_COLORS' variable is not set, '$LSCOLORS' variable is checked instead. This variable is used by ls programs on unix systems such as Mac and BSDs. This variable has a simple syntax and supports 8 colors and bold attribute.

If both of these environment variables are not set, then lf fallbacks to its default colorscheme. Default lf colors are taken from GNU dircolors defaults. These defaults use 8 basic colors and bold attribute.

Keeping this mechanism in mind, you can configure lf colors in two different ways. First, you can configure 8 basic colors used by your terminal and lf should pick up those colors automatically. Depending on your terminal, you should be able to select your colors from a 24-bit palette. This is the recommended approach as colors used by other programs will also match each other.

Second, you can set the values of environmental variables mentioned above for fine grained customization. This is useful to change colors used for different file types and extensions. '$LS_COLORS' is more powerful than '$LSCOLORS' and it can be used even when GNU programs are not installed on the system. You can combine this second method with the first method for best results.

Package Files

app.go client.go colors.go complete.go doc.go docstring.go eval.go main.go misc.go nav.go opts.go os.go parse.go removediacritics.go scan.go server.go ui.go

Package main imports 25 packages (graph). Updated 2018-12-03. Refresh now. Tools for package owners.