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add documentation for remote commands

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Mentioned in #36.
This commit is contained in:
Gokcehan 2017-02-11 16:14:41 +03:00
parent 46a4378531
commit de1168fb96
3 changed files with 191 additions and 1 deletions
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85
doc.go
View File

@ -68,6 +68,7 @@ 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
@ -221,6 +222,90 @@ 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

87
docstring.go
View File

@ -72,6 +72,7 @@ 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
$id id number of the client
Configuration
@ -233,6 +234,92 @@ would simply work). This option is not set by default as things may behave
unexpectedly at other places.
Remote Commands
One of the more advanced features in lf is remote commands. All clients
connect to a server on startup. It is possible to send commands to all or
any of the connected clients over the common server. This is used internally
to notify file selection changes to other clients.
To use this feature, you need to use a client which supports communicating
with a UNIX-domain socket. OpenBSD implementation of netcat (nc) is one such
example. You can use it to send a command to the socket file:
echo 'send echo hello world' | nc -U /tmp/lf.${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

20
etc/lfrc.example
View File

@ -69,7 +69,13 @@ cmd open-file ${{
}}
# rename current file without overwrite
cmd rename $[ -e "$1" ] || mv "$f" "$1"
cmd rename ${{
if [ -e "$1" ]; then
lf -remote "send $id echo file exists"
else
mv "$f" "$1"
fi
}}
map r push :rename<space>
# show disk usage
@ -104,3 +110,15 @@ cmd compress ${{
tar czvf "$1.tar.gz" "$1"
rm -rf "$1"
}}
# 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
}}