Several functions return information about processes.
list-processes&optional query-only buffer
This command displays a listing of all living processes. In addition,
it finally deletes any process whose status was ‘Exited’ or
‘Signaled’. It returns
The processes are shown in a buffer named *Process List* (unless you specify otherwise using the optional argument buffer), whose major mode is Process Menu mode.
If query-only is non-
nil, it only lists processes
whose query flag is non-
nil. See Query Before Exit.
This function returns a list of all processes that have not been deleted.
(process-list) ⇒ (#<process display-time> #<process shell>)
This function returns the process named name (a string), or
nil if there is none. The argument name can also be a
process object, in which case it is returned.
(get-process "shell") ⇒ #<process shell>
This function returns the command that was executed to start
process. This is a list of strings, the first string being the
program executed and the rest of the strings being the arguments that
were given to the program. For a network, serial, or pipe connection,
this is either
nil, which means the process is running or
t (process is stopped).
(process-command (get-process "shell")) ⇒ ("bash" "-i")
process-contactprocess &optional key
This function returns information about how a network, a serial, or a
pipe connection was set up. When key is
nil, it returns
(hostname service) for a network connection,
(port speed) for a serial connection, and t
for a pipe connection. For an ordinary child process, this function
always returns t when called with a
If key is t, the value is the complete status information
for the connection, server, serial port, or pipe; that is, the list of
keywords and values specified in
make-pipe-process, except that
some of the values represent the current status instead of what you
For a network process, the values include (see
make-network-process for a complete list):
The associated value is the process buffer.
The associated value is the process filter function. See Filter Functions.
The associated value is the process sentinel function. See Sentinels.
In a connection, the address in internal format of the remote peer.
The local address, in internal format.
In a server, if you specified t for service, this value is the actual port number.
:remote are included even if they were not
specified explicitly in
For a serial connection, see
serial-process-configure for the list of keys. For a pipe
make-pipe-process for the list of keys.
If key is a keyword, the function returns the value corresponding to that keyword.
This function returns the PID of process. This is an
integral number that distinguishes the process process from all
other processes running on the same computer at the current time. The
PID of a process is chosen by the operating system kernel
when the process is started and remains constant as long as the
process exists. For network, serial, and pipe connections, this
This function returns the name of process, as a string.
This function returns the status of process-name as a symbol. The argument process-name must be a process, a buffer, or a process name (a string).
The possible values for an actual subprocess are:
for a process that is running.
for a process that is stopped but continuable.
for a process that has exited.
for a process that has received a fatal signal.
for a network, serial, or pipe connection that is open.
for a network, serial, or pipe connection that is closed. Once a connection is closed, you cannot reopen it, though you might be able to open a new connection to the same place.
for a non-blocking connection that is waiting to complete.
for a non-blocking connection that has failed to complete.
for a network server that is listening.
if process-name is not the name of an existing process.
(process-status (get-buffer "*shell*")) ⇒ run
For a network, serial, or pipe connection,
returns one of the symbols
The latter means that the other side closed the connection, or Emacs
delete-process. The value
stop means that
stop-process was called on the connection.
This function returns non-
nil if process is alive. A
process is considered alive if its status is
This function returns the symbol
network for a network
connection or server,
serial for a serial port connection,
pipe for a pipe connection, or
real for a subprocess
created for running a program.
This function returns the exit status of process or the signal
number that killed it. (Use the result of
determine which of those it is.) If process has not yet
terminated, the value is 0. For network, serial, and pipe connections
that are already closed, the value is either 0 or 256, depending on
whether the connection was closed normally or abnormally.
This function returns the terminal name that process is using for
its communication with Emacs—or
nil if it is using pipes
instead of a pty (see process-connection-type in
Asynchronous Processes). If process represents a program
running on a remote host, the terminal name used by that program on
the remote host is provided as process property
process represents a network, serial, or pipe connection, the
This function returns a cons cell
(decode . encode),
describing the coding systems in use for decoding output from, and
encoding input to, process (see Coding Systems).
set-process-coding-systemprocess &optional decoding-system encoding-system
This function specifies the coding systems to use for subsequent output from and input to process. It will use decoding-system to decode subprocess output, and encoding-system to encode subprocess input.
Every process also has a property list that you can use to store miscellaneous values associated with the process.
This function returns the value of the propname property of process.
process-putprocess propname value
This function sets the value of the propname property of process to value.
This function returns the process plist of process.
This function sets the process plist of process to plist.