# c

###
Module

c

###
Module Summary

Command interface module.

###
Description

This module enables users to enter the short form of some commonly used commands.

Note

These functions are intended for interactive use in the Erlang shell only. The module prefix can be omitted.

###
Exports

####
bt(Pid) -> ok | undefined

### Types

Pid = pid()

Stack backtrace for a process. Equivalent to erlang:process_display(Pid, backtrace).

####
c(Module) -> {ok, ModuleName} | error

### Types

Module = file:name()
ModuleName = module()

Works like c(Module, []).

####
c(Module, Options) -> {ok, ModuleName} | error

### Types

Module = file:name()
Options = [compile:option()] | compile:option()
ModuleName = module()

Compiles and then purges and loads the code for a module. Module can be either a module name or a source file path, with or without .erl extension.

If Module is a string, it is assumed to be a source file path, and the compiler will attempt to compile the source file with the options Options. If compilation fails, the old object file (if any) is deleted.

If Module is an atom, a source file with that exact name or with .erl extension will be looked for. If found, the source file is compiled with the options Options. If compilation fails, the old object file (if any) is deleted.

If Module is an atom and is not the path of a source file, then the code path is searched to locate the object file for the module and extract its original compiler options and source path. If the source file is not found in the original location, filelib:find_source/1 is used to search for it relative to the directory of the object file.

The source file is compiled with the the original options appended to the given Options, the output replacing the old object file if and only if compilation succeeds.

Notice that purging the code means that any processes lingering in old code for the module are killed without warning. For more information, see the code module.

####
c(Module, Options, Filter) -> {ok, ModuleName} | error
OTP 20.0

### Types

Module = atom()
Options = [compile:option()]
Filter = fun((compile:option()) -> boolean())
ModuleName = module()

Compiles and then purges and loads the code for module Module, which must be an atom.

The code path is searched to locate the object file for module Module and extract its original compiler options and source path. If the source file is not found in the original location, filelib:find_source/1 is used to search for it relative to the directory of the object file.

The source file is compiled with the the original options appended to the given Options, the output replacing the old object file if and only if compilation succeeds. The function Filter specifies which elements to remove from the original compiler options before the new options are added. The Filter fun should return true for options to keep, and false for options to remove.

Notice that purging the code means that any processes lingering in old code for the module are killed without warning. For more information, see the code module.

####
cd(Dir) -> ok

### Types

Dir = file:name()

Changes working directory to Dir, which can be a relative name, and then prints the name of the new working directory.

Example:

    2> cd("../erlang").
    /home/ron/erlang

####
erlangrc(PathList) -> {ok, file:filename()} | {error, term()}
OTP 21.0

### Types

PathList = [Dir :: file:name()]

Search PathList and load .erlang resource file if found.

####
flush() -> ok

Flushes any messages sent to the shell.

####
help() -> ok

Displays help information: all valid shell internal commands, and commands in this module.

####
h(Module :: module()) -> h_return()
OTP 23.0

### Types

h_return() =
ok | {error, missing | {unknown_format, unicode:chardata()}}

Print the documentation for Module

####
h(Module :: module(), Function :: function()) -> hf_return()
OTP 23.0

### Types

h_return() =
ok | {error, missing | {unknown_format, unicode:chardata()}}
hf_return() = h_return() | {error, function_missing}

Print the documentation for all Module:Functions (regardless of arity).

####
h(Module :: module(), Function :: function(), Arity :: arity()) ->
hf_return()
OTP 23.0

### Types

h_return() =
ok | {error, missing | {unknown_format, unicode:chardata()}}
hf_return() = h_return() | {error, function_missing}

Print the documentation for Module:Function/Arity.

####
hcb(Module :: module()) -> h_return()
OTP 23.0

### Types

h_return() =
ok | {error, missing | {unknown_format, unicode:chardata()}}

Print the callback documentation for Module

####
hcb(Module :: module(), Callback :: atom()) -> hcb_return()
OTP 23.0

### Types

h_return() =
ok | {error, missing | {unknown_format, unicode:chardata()}}
hcb_return() = h_return() | {error, callback_missing}

Print the callback documentation for all Module:Callbacks (regardless of arity).

####
hcb(Module :: module(), Callback :: atom(), Arity :: arity()) ->
hcb_return()
OTP 23.0

### Types

h_return() =
ok | {error, missing | {unknown_format, unicode:chardata()}}
hcb_return() = h_return() | {error, callback_missing}

Print the callback documentation for Module:Callback/Arity.

####
ht(Module :: module()) -> h_return()
OTP 23.0

### Types

h_return() =
ok | {error, missing | {unknown_format, unicode:chardata()}}

Print the type documentation for Module

####
ht(Module :: module(), Type :: atom()) -> ht_return()
OTP 23.0

### Types

h_return() =
ok | {error, missing | {unknown_format, unicode:chardata()}}
ht_return() = h_return() | {error, type_missing}

Print the type documentation for Type in Module regardless of arity.

####
ht(Module :: module(), Type :: atom(), Arity :: arity()) ->
ht_return()
OTP 23.0

### Types

h_return() =
ok | {error, missing | {unknown_format, unicode:chardata()}}
ht_return() = h_return() | {error, type_missing}

Print the type documentation for Type/Arity in Module.

####
i() -> ok

####
ni() -> ok

i/0 displays system information, listing information about all processes. ni/0 does the same, but for all nodes the network.

####
i(X, Y, Z) -> [{atom(), term()}]

### Types

X = Y = Z = integer() >= 0

Displays information about a process, Equivalent to process_info(pid(X, Y, Z)), but location transparent.

####
l(Module) -> code:load_ret()

### Types

Module = module()

Purges and loads, or reloads, a module by calling code:purge(Module) followed by code:load_file(Module).

Notice that purging the code means that any processes lingering in old code for the module are killed without warning. For more information, see code/3.

####
lc(Files) -> ok

### Types

Files = [File]
File

Compiles a list of files by calling compile:file(File, [report_errors, report_warnings]) for each File in Files.

For information about File, see file:filename().

####
lm() -> [code:load_ret()]
OTP 20.0

Reloads all currently loaded modules that have changed on disk (see mm()). Returns the list of results from calling l(M) for each such M.

####
ls() -> ok

Lists files in the current directory.

####
ls(Dir) -> ok

### Types

Dir = file:name()

Lists files in directory Dir or, if Dir is a file, only lists it.

####
m() -> ok

Displays information about the loaded modules, including the files from which they have been loaded.

####
m(Module) -> ok

### Types

Module = module()

Displays information about Module.

####
mm() -> [module()]
OTP 20.0

Lists all modified modules. Shorthand for code:modified_modules/0.

####
memory() -> [{Type, Size}]

### Types

Type = atom()
Size = integer() >= 0

Memory allocation information. Equivalent to erlang:memory/0.

####
memory(Type) -> Size

####
memory(Types) -> [{Type, Size}]

### Types

Types = [Type]
Type = atom()
Size = integer() >= 0

Memory allocation information. Equivalent to erlang:memory/1.

####
nc(File) -> {ok, Module} | error

####
nc(File, Options) -> {ok, Module} | error

### Types

File = file:name()
Options = [Option] | Option
Option = compile:option()
Module = module()

Compiles and then loads the code for a file on all nodes. Options defaults to []. Compilation is equivalent to:

    compile:file(File, Options ++ [report_errors, report_warnings])

####
nl(Module) -> abcast | error

### Types

Module = module()

Loads Module on all nodes.

####
pid(X, Y, Z) -> pid()

### Types

X = Y = Z = integer() >= 0

Converts X, Y, Z to pid <X.Y.Z>. This function is only to be used when debugging.

####
pwd() -> ok

Prints the name of the working directory.

####
q() -> no_return()

This function is shorthand for init:stop(), that is, it causes the node to stop in a controlled fashion.

####
regs() -> ok

####
nregs() -> ok

regs/0 displays information about all registered processes. nregs/0 does the same, but for all nodes in the network.

####
uptime() -> ok
OTP 18.0

Prints the node uptime (as specified by erlang:statistics(wall_clock)) in human-readable form.

####
xm(ModSpec) -> void()

### Types

ModSpec = Module | Filename
Module = atom()
Filename = string()

Finds undefined functions, unused functions, and calls to deprecated functions in a module by calling xref:m/1.

####
y(File) -> YeccRet

### Types

File = name()
YeccRet

Generates an LALR-1 parser. Equivalent to:

    yecc:file(File)

For information about File = name(), see filename(3). For information about YeccRet, see yecc:file/2.

####
y(File, Options) -> YeccRet

### Types

File = name()
Options, YeccRet

Generates an LALR-1 parser. Equivalent to:

    yecc:file(File, Options)

For information about File = name(), see filename(3). For information about Options and YeccRet, see yecc:file/2.

###
See Also

filename(3), compile(3), erlang(3), yecc(3), xref(3)