# Class `luci.sys`

## Functions

call (...) | Execute a given shell command and return the error code
dmesg () | Retrieves the output of the "dmesg" command.
exec (command) | Execute a given shell command and capture its standard output
getenv (var) | Retrieve environment variables.
hostname (String) | Get or set the current hostname.
httpget (url, stream, target) | Returns the contents of a documented referred by an URL.
mounts () | Retrieve information about currently mounted file systems.
reboot () | Initiate a system reboot.
syslog () | Retrieves the output of the "logread" command.
uniqueid (bytes) | Generates a random id with specified length.
uptime () | Returns the current system uptime stats.

## Functions

call (...)
  Execute a given shell command and return the error code

  ### Parameters

  - ...: Command to call

  ### Return value:

  Error code of the command
dmesg ()
  Retrieves the output of the "dmesg" command.

  ### Return value:

  String containing the current log buffer
exec (command)
  Execute a given shell command and capture its standard output

  ### Parameters

  - command: Command to call

  ### Return value:

  String containing the return the output of the command
getenv (var)
  Retrieve environment variables. If no variable is given then a table containing the whole environment is returned otherwise this function returns the corresponding string value for the given name or nil if no such variable exists.

  ### Parameters

  - var: Name of the environment variable to retrieve (optional)

  ### Return values:

  1. String containing the value of the specified variable
  2. Table containing all variables if no variable name is given
hostname (String)
  Get or set the current hostname.

  ### Parameters

  - String: containing a new hostname to set (optional)

  ### Return value:

  String containing the system hostname
httpget (url, stream, target)
  Returns the contents of a documented referred by an URL.

  ### Parameters

  - url: The URL to retrieve
  - stream: Return a stream instead of a buffer
  - target: Directly write to target file name

  ### Return value:

  String containing the contents of given the URL
mounts ()
  Retrieve information about currently mounted file systems.

  ### Return value:

  Table containing mount information
reboot ()
  Initiate a system reboot.

  ### Return value:

  Return value of os.execute()
syslog ()
  Retrieves the output of the "logread" command.

  ### Return value:

  String containing the current log buffer
uniqueid (bytes)
  Generates a random id with specified length.

  ### Parameters

  - bytes: Number of bytes for the unique id

  ### Return value:

  String containing hex encoded id
uptime ()
  Returns the current system uptime stats.

  ### Return value:

  String containing total uptime in seconds