# Obtaining Process Information >![](../../public_sys-resources/icon-note.gif) **NOTE:** >The initial APIs of this module are supported since API version 7. Newly added APIs will be marked with a superscript to indicate their earliest API version. ## Modules to Import ``` import process from '@ohos.process'; ``` ## Required Permissions None ## Attributes

Name	Type	Readable	Writable	Description
egid	number	Yes	No	Effective group identifier (EGID) of a process.
euid	number	Yes	No	Effective user identifier (EUID) of a process.
gid	number	Yes	No	Group identifier (GID) of a process.
uid	number	Yes	No	User identifier (UID) of a process.
groups	number[]	Yes	No	Array with supplementary group IDs.
pid	number	Yes	No	Process ID (PID) of a process.
ppid	number	Yes	No	Parent process ID (PPID) of a process.
tid⁸⁺	number	Yes	No	Thread ID (TID) of a process.

## ChildProcess Provides methods for a process to obtain the standard input and output of its child processes, send signals, and close its child processes. ### Attributes

Name	Type	Readable	Writable	Description
pid	number	Yes	No	PID of the child process.
ppid	number	Yes	No	PPID of the child process.
exitCode	number	Yes	No	Exit code of the child process.
killed	boolean	Yes	No	Whether the parent process successfully sends a signal to the child process to terminate it.

### wait wait\(\): Promise Waits until the child process ends. This method uses a promise to return the exit code of the child process. - Return values

Type	Description
Promise<number>	Promise used to return the exit code of the child process.

- Example ``` var child = process.runCmd('ls'); var result = child.wait(); result.then(val=>{ console.log("result = " + val); }) ``` ### getOutput getOutput\(\): Promise Obtains the standard output of the child process. - Return values

Type	Description
Promise<Uint8Array>	Promise used to return the standard output in a Uint8Array.

- Example ``` var child = process.runCmd('ls'); var result = child.wait(); child.getOutput.then(val=>{ console.log("child.getOutput = " + val); }) ``` ### getErrorOutput getErrorOutput\(\): Promise Obtains the standard error output of the child process. - Return values

Type	Description
Promise<Uint8Array>	Promise used to return the standard error output in a Uint8Array.

- Example ``` var child = process.runCmd('madir test.text'); var result = child.wait(); child.getErrorOutput.then(val=>{ console.log("child.getErrorOutput= " + val); }) ``` ### close close\(\): void Closes the child process in running. - Example ``` var child = process.runCmd('sleep 5; ls'); child.close(); ``` ### kill kill\(signal: number | string\): void Sends a signal to the specified child process to terminate it. - Parameters

Name	Type	Mandatory	Description
signal	number \| string	Yes	Number or string to send.

- Example ``` var child = process.runCmd('sleep 5; ls'); child.kill(9); ``` ## process.isIsolatedProcess⁸⁺ isIsolatedProcess\(\): boolean Checks whether the process is isolated. - Return values

Type	Description
boolean	Returns true if the process is isolated; returns false otherwise.

- Example ``` var result = process.isIsolatedProcess(); ``` ## process.isAppUid⁸⁺ isAppUid\(v:number\): boolean Checks whether a UID belongs to this app. - Parameters

Name	Type	Mandatory	Description
v	number	Yes	UID.

- Return values

Type	Description
boolean	Returns true if the UID is the app's UID; returns false otherwise.

- Example ``` var result = process.isAppUid(688); ``` ## process.is64Bit⁸⁺ is64Bit\(\): boolean Checks whether the operating environment is of 64-bit. - Return values

Type	Description
boolean	Returns true if the operating environment is of 64-bit; returns false otherwise.

- Example ``` var ressult = process.is64Bit(); ``` ## process.getUidForName⁸⁺ getUidForName\(v:string\): number Obtains the process UID based on the process name. - Parameters

Name	Type	Mandatory	Description
v	string	Yes	Process name.

- Return values

Type	Description
number	Process UID.

- Example ``` var pres = process.getUidForName("tool") ``` ## process.getThreadPriority⁸⁺ getThreadPriority\(v:number\): number Obtains the thread priority based on the specified TID. - Parameters

Name	Type	Mandatory	Description
v	number	Yes	TID.

- Return values

Type	Description
number	Priority of the thread.

- Example ``` var tid = process.tid; var pres = process.getThreadPriority(tid); ``` ## process.getStartRealtime⁸⁺ getStartRealtime\(\) :number Obtains the duration, in milliseconds, from the time the system starts to the time the process starts. - Return values

Type	Description
number	Time duration obtained.

- Example ``` var realtime = process.getStartRealtime(); ``` ## process.getAvailableCores⁸⁺ getAvailableCores\(\) :number\[\] Obtains the number of CPU cores available for the current process on a multi-core device. - Return values

Type	Description
number[]	Number of cores available for the process.

- Example ``` var result = getAvailableCores(); ``` ## process.getPastCputime⁸⁺ getPastCputime\(\) :number Obtains the CPU time \(in milliseconds\) from the time the process starts to the current time. - Return values

Type	Description
number	CPU time obtained.

- Example ``` var result = process.getPastCputime() ; ``` ## process.getSystemConfig⁸⁺ getSystemConfig\(name:number\): number Obtains the system configuration. - Parameters

Name	Type	Mandatory	Description
name	number	Yes	System configuration parameter name.

- Return values

Type	Description
number	System configuration obtained.

- Example ``` var _SC_ARG_MAX = 0 var pres = process.getSystemConfig(_SC_ARG_MAX) ``` ## process.getEnvironmentVar⁸⁺ getEnvironmentVar\(name:string\): string Obtains the value of an environment variable. - Parameters

Name	Type	Mandatory	Description
name	string	Yes	Environment variable name.

- Return values

Type	Description
string	Value of the environment variable.

- Example ``` var pres = process.getEnvironmentVar("PATH") ``` ## process.runCmd runCmd\(command: string, options?: \{ timeout : number, killSignal : number | string, maxBuffer : number \}\) : ChildProcess Forks a new process to run a shell command and returns the **ChildProcess** object. - Parameters

Name	Type	Mandatory	Description
command	string	Yes	Shell command to run.
options	Object	No	Related parameters.

**Table 1** options

Name	Type	Mandatory	Description
timeout	number	No	Maximum running time (in ms) of the child process. When the running time of the child process exceeds the value of this parameter, the parent process sends a killSignal to the child process to terminate it. The default value is 0.
killSignal	number \| string	No	Signal sent to the child process when the running time of a child process exceeds the timeout period. The default value is SIGTERM.
maxBuffer	number	No	Maximum buffer size for the standard input and output of the child process. When the size is exceeded, the child process will be terminated. The default value is *1024 1024**.

- Return values

Type	Description
ChildProcess	ChildProcess object.

- Example ``` var child = process.runCmd('ls', { maxBuffer : 2 }); var result = child.wait(); child.getOutput.then(val=>{ console.log("child.getOutput = " + val); }) ``` ## process.abort abort\(\): void Aborts a process and generates a core file. This method will cause a process to exit immediately. Exercise caution when using this method. - Example ``` process.abort(); ``` ## process.on on\(type: string, listener: EventListener\): void Stores the events triggered by the user. - Parameters

Name	Type	Mandatory	Description
type	string	Yes	Type of the events to store.
listener	EventListener	Yes	Callback invoked to return the event.

**Table 2** EventListener

Name	Description
EventListener = (evt: Object) => void	Event to store.

- Example ``` process.on("data", (e)=>{ console.log("data callback"); }) ``` ## process.off off\(type: string\): boolean Deletes the event stored by the user. - Parameters

Name	Type	Mandatory	Description
type	string	Yes	Type of the event to delete.

- Return values

Type	Description
boolean	Returns true if the event is deleted; returns false otherwise.

- Example ``` process.on("data", (e)=>{ console.log("data callback"); }) var result = process.off("data"); ``` ## process.exit exit\(code: number\): void Terminates this process. - Parameters

Name	Type	Mandatory	Description
code	number	Yes	Exit code of the process.

- Example ``` process.exit(0); ``` ## process.cwd cwd\(\): string Obtains the working directory of this process. - Example ``` var path = process.cwd(); ``` ## process.chdir chdir\(dir: string\): void Changes the working directory of this process. - Parameters

Name	Type	Mandatory	Description
dir	string	Yes	New working directory.

- Example ``` process.chdir('/system'); ``` ## process.uptime uptime\(\): number Obtains the running time of this process. - Return values

Type	Description
number	Running time of the process, in seconds.

- Example ``` var time = process.uptime(); ``` ## process.kill kill\(pid: number, signal: number\): boolean Sends a signal to the specified process to terminate it. - Parameters

Name	Type	Mandatory	Description
pid	number	Yes	PID of the process, to which the signal will be sent.
signal	number	Yes	Signal to send.

- Return values

Type	Description
boolean	Returns true if the signal is sent successfully; returns false otherwise.

- Example ``` var pres = process.pid var result = that.kill(pres, 28) ```