Shell (Apache Hadoop Common 3.4.1.100-eep-941 API)

java.lang.Object
- org.apache.hadoop.util.Shell

Direct Known Subclasses:

DF, Shell.ShellCommandExecutor, Stat
```
@Public
@Evolving
public abstract class Shell
extends java.lang.Object
```
A base class for running a Shell command. Shell can be used to run shell commands like du or df. It also offers facilities to gate commands by time-intervals.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static interface`	`Shell.CommandExecutor`
`static class`	`Shell.ExitCodeException`	This is an IOException with exit code added.
`static class`	`Shell.OSType`
`static class`	`Shell.ShellCommandExecutor`	A simple shell command executor.

Field Summary

Fields
Modifier and Type	Field	Description
`static java.lang.String`	`ENV_DEBUG_OPTS`
`static java.lang.String`	`ENV_HADOOP_HOME`	Environment variable for Hadoop's home dir: "HADOOP_HOME".
`static java.lang.String`	`ENV_HADOOP_OPTS`
`static java.lang.String`	`ENV_MAPR_JMX_OPTS`
`static java.lang.String`	`ENV_NAME_REGEX`	Regular expression for environment variables: "[A-Za-z_][A-Za-z0-9_]*".
`static boolean`	`FREEBSD`
`protected boolean`	`inheritParentEnv`	Indicates if the parent env vars should be inherited or not
`static boolean`	`isSetsidAvailable`	Flag which is true if setsid exists.
`static java.lang.String`	`LINK_COMMAND`	a Unix command to create a link: "ln".
`static boolean`	`LINUX`
`static org.slf4j.Logger`	`LOG`
`static boolean`	`MAC`
`static Shell.OSType`	`osType`	Get the type of the operating system, as determined from parsing the `os.name` property.
`static boolean`	`OTHER`
`static boolean`	`PPC_64`
`static java.lang.String`	`READ_LINK_COMMAND`	a Unix command to get a link target: "readlink".
`static java.lang.String`	`SET_GROUP_COMMAND`	a Unix command to set the change user's groups list: "chgrp".
`static java.lang.String`	`SET_OWNER_COMMAND`	a Unix command to set owner: "chown".
`static java.lang.String`	`SET_PERMISSION_COMMAND`	a Unix command to set permission: "chmod".
`static boolean`	`SOLARIS`
`static java.lang.String`	`SYSPROP_HADOOP_HOME_DIR`	System property for the Hadoop home directory: "hadoop.home.dir".
`protected long`	`timeOutInterval`	Time after which the executing script would be timedout.
`static java.lang.String`	`TOKEN_SEPARATOR_REGEX`	Token separator regex used to parse Shell tool outputs.
`static java.lang.String`	`USER_NAME_COMMAND`	a Unix command to get the current user's name: "whoami".
`static boolean`	`WINDOWS`
`static int`	`WINDOWS_MAX_SHELL_LENGHT`	Deprecated. use the correctly spelled constant.
`static int`	`WINDOWS_MAX_SHELL_LENGTH`	Maximum command line length in Windows KB830473 documents this as 8191
`static java.lang.Object`	`WindowsProcessLaunchLock`	Windows `CreateProcess` synchronization object.
`static java.lang.String`	`WINUTILS`	Deprecated. use one of the exception-raising getter methods, specifically `getWinUtilsPath()` or `getWinUtilsFile()`

Constructor Summary

Constructors
Modifier	Constructor	Description
`protected`	`Shell()`	Create an instance with no minimum interval between runs; stderr is not merged with stdout.
`protected`	`Shell(long interval)`	Create an instance with a minimum interval between executions; stderr is not merged with stdout.
`protected`	`Shell(long interval, boolean redirectErrorStream)`	Create a shell instance which can be re-executed when the `run()` method is invoked with a given elapsed time between calls.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`static java.io.File`	`appendScriptExtension(java.io.File parent, java.lang.String basename)`	Returns a File referencing a script with the given basename, inside the given parent directory.
`static java.lang.String`	`appendScriptExtension(java.lang.String basename)`	Returns a script file name with the given basename.
`static java.lang.String`	`bashQuote(java.lang.String arg)`	Quote the given arg so that bash will interpret it as a single value.
`static boolean`	`checkIsBashSupported()`
`static boolean`	`checkUserExists(java.lang.String user)`	Check that user exists on the node
`static void`	`checkWindowsCommandLineLength(java.lang.String... commands)`	Checks if a given command (String[]) fits in the Windows maximum command line length Note that the input is expected to already include space delimiters, no extra count will be added for delimiters.
`static void`	`destroyAllShellProcesses()`	Static method to destroy all running `Shell` processes.
`static java.lang.String`	`execCommand(java.lang.String... cmd)`	Static method to execute a shell command.
`static java.lang.String`	`execCommand(java.util.Map<java.lang.String,java.lang.String> env, java.lang.String... cmd)`	Static method to execute a shell command.
`static java.lang.String`	`execCommand(java.util.Map<java.lang.String,java.lang.String> env, java.lang.String[] cmd, long timeout)`	Static method to execute a shell command.
`static java.util.Set<Shell>`	`getAllShells()`	Static method to return a Set of all `Shell` objects.
`static java.lang.String[]`	`getCheckProcessIsAliveCommand(java.lang.String pid)`	Return a command for determining if process with specified pid is alive.
`java.lang.String`	`getEnvironment(java.lang.String env)`	Get an environment variable.
`static java.lang.String`	`getEnvironmentVariableRegex()`	Return a regular expression string that match environment variables.
`protected abstract java.lang.String[]`	`getExecString()`	return an array containing the command name and its parameters.
`int`	`getExitCode()`	get the exit code.
`static java.lang.String[]`	`getGetPermissionCommand()`	Return a command to get permission information.
`static java.lang.String[]`	`getGroupsCommand()`	a Unix command to get the current user's groups list.
`static java.lang.String[]`	`getGroupsForUserCommand(java.lang.String user)`	A command to get a given user's groups list.
`static java.lang.String[]`	`getGroupsIDForUserCommand(java.lang.String user)`	A command to get a given user's group id list.
`static java.lang.String`	`getHadoopHome()`	Get the Hadoop home directory.
`static java.lang.Long`	`getMemlockLimit(java.lang.Long ulimit)`	Static method to return the memory lock limit for datanode.
`java.lang.Process`	`getProcess()`	get the current sub-process executing the given command.
`static java.io.File`	`getQualifiedBin(java.lang.String executable)`	Fully qualify the path to a binary that should be in a known hadoop bin location.
`static java.lang.String`	`getQualifiedBinPath(java.lang.String executable)`	Fully qualify the path to a binary that should be in a known hadoop bin location.
`static java.lang.String[]`	`getReadlinkCommand(java.lang.String link)`	Return a command to read the target of the a symbolic link.
`static java.lang.String[]`	`getRunScriptCommand(java.io.File script)`	Returns a command to run the given script.
`static java.lang.String[]`	`getSetOwnerCommand(java.lang.String owner)`	Return a command to set owner.
`static java.lang.String[]`	`getSetPermissionCommand(java.lang.String perm, boolean recursive)`	Return a command to set permission.
`static java.lang.String[]`	`getSetPermissionCommand(java.lang.String perm, boolean recursive, java.lang.String file)`	Return a command to set permission for specific file.
`static java.lang.String[]`	`getSignalKillCommand(int code, java.lang.String pid)`	Return a command to send a signal to a given pid.
`static java.lang.String[]`	`getSymlinkCommand(java.lang.String target, java.lang.String link)`	Return a command to create symbolic links.
`static java.lang.String[]`	`getUsersForNetgroupCommand(java.lang.String netgroup)`	A command to get a given netgroup's user list.
`java.lang.Thread`	`getWaitingThread()`	get the thread that is waiting on this instance of `Shell`.
`static java.io.File`	`getWinUtilsFile()`	Get a file reference to winutils.
`static java.lang.String`	`getWinUtilsPath()`	Locate the winutils binary, or fail with a meaningful exception and stack trace as an RTE.
`static boolean`	`hasWinutilsPath()`	Predicate to indicate whether or not the path to winutils is known.
`static boolean`	`isJava7OrAbove()`	Deprecated. This call isn't needed any more: please remove uses of it.
`static boolean`	`isJavaVersionAtLeast(int version)`	Query to see if major version of Java specification of the system is equal or greater than the parameter.
`boolean`	`isTimedOut()`	To check if the passed script to shell command executor timed out or not.
`protected abstract void`	`parseExecResult(java.io.BufferedReader lines)`	Parse the execution result.
`protected void`	`run()`	Check to see if a command needs to be executed and execute if needed.
`protected void`	`setEnvironment(java.util.Map<java.lang.String,java.lang.String> env)`	Set the environment for the command.
`protected void`	`setWorkingDirectory(java.io.File dir)`	Set the working directory.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - LOG
```
public static final org.slf4j.Logger LOG
```
  - SYSPROP_HADOOP_HOME_DIR
```
public static final java.lang.String SYSPROP_HADOOP_HOME_DIR
```
    System property for the Hadoop home directory: "hadoop.home.dir".
    
    See Also:
    
    Constant Field Values
  - ENV_HADOOP_HOME
```
public static final java.lang.String ENV_HADOOP_HOME
```
    Environment variable for Hadoop's home dir: "HADOOP_HOME".
    
    See Also:
    
    Constant Field Values
  - ENV_HADOOP_OPTS
```
public static final java.lang.String ENV_HADOOP_OPTS
```
    See Also:
    
    Constant Field Values
  - ENV_MAPR_JMX_OPTS
```
public static final java.lang.String ENV_MAPR_JMX_OPTS
```
    See Also:
    
    Constant Field Values
  - ENV_DEBUG_OPTS
```
public static final java.lang.String ENV_DEBUG_OPTS
```
    See Also:
    
    Constant Field Values
  - WINDOWS_MAX_SHELL_LENGTH
```
public static final int WINDOWS_MAX_SHELL_LENGTH
```
    Maximum command line length in Windows KB830473 documents this as 8191
    
    See Also:
    
    Constant Field Values
  - WINDOWS_MAX_SHELL_LENGHT
```
@Deprecated
public static final int WINDOWS_MAX_SHELL_LENGHT
```
    Deprecated.
    use the correctly spelled constant.
    
    mis-spelling of WINDOWS_MAX_SHELL_LENGTH.
    
    See Also:
    
    Constant Field Values
  - USER_NAME_COMMAND
```
public static final java.lang.String USER_NAME_COMMAND
```
    a Unix command to get the current user's name: "whoami".
    
    See Also:
    
    Constant Field Values
  - WindowsProcessLaunchLock
```
public static final java.lang.Object WindowsProcessLaunchLock
```
    Windows CreateProcess synchronization object.
  - osType
```
public static final Shell.OSType osType
```
    Get the type of the operating system, as determined from parsing the os.name property.
  - WINDOWS
```
public static final boolean WINDOWS
```
  - SOLARIS
```
public static final boolean SOLARIS
```
  - MAC
```
public static final boolean MAC
```
  - FREEBSD
```
public static final boolean FREEBSD
```
  - LINUX
```
public static final boolean LINUX
```
  - OTHER
```
public static final boolean OTHER
```
  - PPC_64
```
public static final boolean PPC_64
```
  - ENV_NAME_REGEX
```
public static final java.lang.String ENV_NAME_REGEX
```
    Regular expression for environment variables: "[A-Za-z_][A-Za-z0-9_]*".
    
    See Also:
    
    Constant Field Values
  - SET_PERMISSION_COMMAND
```
public static final java.lang.String SET_PERMISSION_COMMAND
```
    a Unix command to set permission: "chmod".
    
    See Also:
    
    Constant Field Values
  - SET_OWNER_COMMAND
```
public static final java.lang.String SET_OWNER_COMMAND
```
    a Unix command to set owner: "chown".
    
    See Also:
    
    Constant Field Values
  - SET_GROUP_COMMAND
```
public static final java.lang.String SET_GROUP_COMMAND
```
    a Unix command to set the change user's groups list: "chgrp".
    
    See Also:
    
    Constant Field Values
  - LINK_COMMAND
```
public static final java.lang.String LINK_COMMAND
```
    a Unix command to create a link: "ln".
    
    See Also:
    
    Constant Field Values
  - READ_LINK_COMMAND
```
public static final java.lang.String READ_LINK_COMMAND
```
    a Unix command to get a link target: "readlink".
    
    See Also:
    
    Constant Field Values
  - timeOutInterval
```
protected long timeOutInterval
```
    Time after which the executing script would be timedout.
  - inheritParentEnv
```
protected boolean inheritParentEnv
```
    Indicates if the parent env vars should be inherited or not
  - WINUTILS
```
@Deprecated
public static final java.lang.String WINUTILS
```
    Deprecated.
    use one of the exception-raising getter methods, specifically getWinUtilsPath() or getWinUtilsFile()
    
    Location of winutils as a string; null if not found.
    Important: caller must check for this value being null. The lack of such checks has led to many support issues being raised.
  - isSetsidAvailable
```
public static final boolean isSetsidAvailable
```
    Flag which is true if setsid exists.
  - TOKEN_SEPARATOR_REGEX
```
public static final java.lang.String TOKEN_SEPARATOR_REGEX
```
    Token separator regex used to parse Shell tool outputs.
- Constructor Detail
  - Shell
```
protected Shell()
```
    Create an instance with no minimum interval between runs; stderr is not merged with stdout.
  - Shell
```
protected Shell(long interval)
```
    Create an instance with a minimum interval between executions; stderr is not merged with stdout.
    
    Parameters:
    
    interval - interval in milliseconds between command executions.
  - Shell
```
protected Shell(long interval,
                boolean redirectErrorStream)
```
    Create a shell instance which can be re-executed when the run() method is invoked with a given elapsed time between calls.
    
    Parameters:
    
    interval - the minimum duration in milliseconds to wait before re-executing the command. If set to 0, there is no minimum.
    
    redirectErrorStream - should the error stream be merged with the normal output stream?
- Method Detail
  - isJava7OrAbove
```
@Deprecated
public static boolean isJava7OrAbove()
```
    Deprecated.
    This call isn't needed any more: please remove uses of it.
    
    query to see if system is Java 7 or later. Now that Hadoop requires Java 7 or later, this always returns true.
    
    Returns:
    
    true, always.
  - isJavaVersionAtLeast
```
public static boolean isJavaVersionAtLeast(int version)
```
    Query to see if major version of Java specification of the system is equal or greater than the parameter.
    
    Parameters:
    
    version - 8, 9, 10 etc.
    
    Returns:
    
    comparison with system property, always true for 8
  - checkWindowsCommandLineLength
```
public static void checkWindowsCommandLineLength(java.lang.String... commands)
                                          throws java.io.IOException
```
    Checks if a given command (String[]) fits in the Windows maximum command line length Note that the input is expected to already include space delimiters, no extra count will be added for delimiters.
    
    Parameters:
    
    commands - command parts, including any space delimiters
    
    Throws:
    
    java.io.IOException - raised on errors performing I/O.
  - bashQuote
```
@Private
public static java.lang.String bashQuote(java.lang.String arg)
```
    Quote the given arg so that bash will interpret it as a single value. Note that this quotes it for one level of bash, if you are passing it into a badly written shell script, you need to fix your shell script.
    
    Parameters:
    
    arg - the argument to quote
    
    Returns:
    
    the quoted string
  - getGroupsCommand
```
public static java.lang.String[] getGroupsCommand()
```
    a Unix command to get the current user's groups list.
    
    Returns:
    
    group command array.
  - getGroupsForUserCommand
```
public static java.lang.String[] getGroupsForUserCommand(java.lang.String user)
```
    A command to get a given user's groups list. If the OS is not WINDOWS, the command will get the user's primary group first and finally get the groups list which includes the primary group. i.e. the user's primary group will be included twice.
    
    Parameters:
    
    user - user.
    
    Returns:
    
    groups for user command.
  - getGroupsIDForUserCommand
```
public static java.lang.String[] getGroupsIDForUserCommand(java.lang.String user)
```
    A command to get a given user's group id list. The command will get the user's primary group first and finally get the groups list which includes the primary group. i.e. the user's primary group will be included twice. This command does not support Windows and will only return group names.
    
    Parameters:
    
    user - user.
    
    Returns:
    
    groups id for user command.
  - checkUserExists
```
public static boolean checkUserExists(java.lang.String user)
```
    Check that user exists on the node
    
    Parameters:
    
    user - - username
    
    Returns:
    
    True if user exists
  - getUsersForNetgroupCommand
```
public static java.lang.String[] getUsersForNetgroupCommand(java.lang.String netgroup)
```
    A command to get a given netgroup's user list.
    
    Parameters:
    
    netgroup - net group.
    
    Returns:
    
    users for net group command.
  - getGetPermissionCommand
```
public static java.lang.String[] getGetPermissionCommand()
```
    Return a command to get permission information.
    
    Returns:
    
    permission command.
  - getSetPermissionCommand
```
public static java.lang.String[] getSetPermissionCommand(java.lang.String perm,
                                                         boolean recursive)
```
    Return a command to set permission.
    
    Parameters:
    
    perm - permission.
    
    recursive - recursive.
    
    Returns:
    
    set permission command.
  - getSetPermissionCommand
```
public static java.lang.String[] getSetPermissionCommand(java.lang.String perm,
                                                         boolean recursive,
                                                         java.lang.String file)
```
    Return a command to set permission for specific file.
    
    Parameters:
    
    perm - String permission to set
    
    recursive - boolean true to apply to all sub-directories recursively
    
    file - String file to set
    
    Returns:
    
    String[] containing command and arguments
  - getSetOwnerCommand
```
public static java.lang.String[] getSetOwnerCommand(java.lang.String owner)
```
    Return a command to set owner.
    
    Parameters:
    
    owner - owner.
    
    Returns:
    
    set owner command.
  - getSymlinkCommand
```
public static java.lang.String[] getSymlinkCommand(java.lang.String target,
                                                   java.lang.String link)
```
    Return a command to create symbolic links.
    
    Parameters:
    
    target - target.
    
    link - link.
    
    Returns:
    
    symlink command.
  - getReadlinkCommand
```
public static java.lang.String[] getReadlinkCommand(java.lang.String link)
```
    Return a command to read the target of the a symbolic link.
    
    Parameters:
    
    link - link.
    
    Returns:
    
    read link command.
  - getCheckProcessIsAliveCommand
```
public static java.lang.String[] getCheckProcessIsAliveCommand(java.lang.String pid)
```
    Return a command for determining if process with specified pid is alive.
    
    Parameters:
    
    pid - process ID
    
    Returns:
    
    a kill -0 command or equivalent
  - getSignalKillCommand
```
public static java.lang.String[] getSignalKillCommand(int code,
                                                      java.lang.String pid)
```
    Return a command to send a signal to a given pid.
    
    Parameters:
    
    code - code.
    
    pid - pid.
    
    Returns:
    
    signal kill command.
  - getEnvironmentVariableRegex
```
public static java.lang.String getEnvironmentVariableRegex()
```
    Return a regular expression string that match environment variables.
    
    Returns:
    
    environment variable regex.
  - appendScriptExtension
```
public static java.io.File appendScriptExtension(java.io.File parent,
                                                 java.lang.String basename)
```
    Returns a File referencing a script with the given basename, inside the given parent directory. The file extension is inferred by platform: ".cmd" on Windows, or ".sh" otherwise.
    
    Parameters:
    
    parent - File parent directory
    
    basename - String script file basename
    
    Returns:
    
    File referencing the script in the directory
  - appendScriptExtension
```
public static java.lang.String appendScriptExtension(java.lang.String basename)
```
    Returns a script file name with the given basename. The file extension is inferred by platform: ".cmd" on Windows, or ".sh" otherwise.
    
    Parameters:
    
    basename - String script file basename
    
    Returns:
    
    String script file name
  - getRunScriptCommand
```
public static java.lang.String[] getRunScriptCommand(java.io.File script)
```
    Returns a command to run the given script. The script interpreter is inferred by platform: cmd on Windows or bash otherwise.
    
    Parameters:
    
    script - File script to run
    
    Returns:
    
    String[] command to run the script
  - getHadoopHome
```
public static java.lang.String getHadoopHome()
                                      throws java.io.IOException
```
    Get the Hadoop home directory. Raises an exception if not found
    
    Returns:
    
    the home dir
    
    Throws:
    
    java.io.IOException - if the home directory cannot be located.
  - getQualifiedBin
```
public static java.io.File getQualifiedBin(java.lang.String executable)
                                    throws java.io.FileNotFoundException
```
    Fully qualify the path to a binary that should be in a known hadoop bin location. This is primarily useful for disambiguating call-outs to executable sub-components of Hadoop to avoid clashes with other executables that may be in the path. Caveat: this call doesn't just format the path to the bin directory. It also checks for file existence of the composed path. The output of this call should be cached by callers.
    
    Parameters:
    
    executable - executable
    
    Returns:
    
    executable file reference
    
    Throws:
    
    java.io.FileNotFoundException - if the path does not exist
  - getQualifiedBinPath
```
public static java.lang.String getQualifiedBinPath(java.lang.String executable)
                                            throws java.io.IOException
```
    Fully qualify the path to a binary that should be in a known hadoop bin location. This is primarily useful for disambiguating call-outs to executable sub-components of Hadoop to avoid clashes with other executables that may be in the path. Caveat: this call doesn't just format the path to the bin directory. It also checks for file existence of the composed path. The output of this call should be cached by callers.
    
    Parameters:
    
    executable - executable
    
    Returns:
    
    executable file reference
    
    Throws:
    
    java.io.FileNotFoundException - if the path does not exist
    
    java.io.IOException - on path canonicalization failures
  - hasWinutilsPath
```
public static boolean hasWinutilsPath()
```
    Predicate to indicate whether or not the path to winutils is known. If true, then WINUTILS is non-null, and both getWinUtilsPath() and getWinUtilsFile() will successfully return this value. Always false on non-windows systems.
    
    Returns:
    
    true if there is a valid path to the binary
  - getWinUtilsPath
```
public static java.lang.String getWinUtilsPath()
```
    Locate the winutils binary, or fail with a meaningful exception and stack trace as an RTE. This method is for use in methods which don't explicitly throw an IOException.
    
    Returns:
    
    the path to WINUTILS_EXE
    
    Throws:
    
    java.lang.RuntimeException - if the path is not resolvable
  - getWinUtilsFile
```
public static java.io.File getWinUtilsFile()
                                    throws java.io.FileNotFoundException
```
    Get a file reference to winutils. Always raises an exception if there isn't one
    
    Returns:
    
    the file instance referring to the winutils bin.
    
    Throws:
    
    java.io.FileNotFoundException - on any failure to locate that file.
  - checkIsBashSupported
```
public static boolean checkIsBashSupported()
                                    throws java.io.InterruptedIOException
```
    Throws:
    
    java.io.InterruptedIOException
  - setEnvironment
```
protected void setEnvironment(java.util.Map<java.lang.String,java.lang.String> env)
```
    Set the environment for the command.
    
    Parameters:
    
    env - Mapping of environment variables
  - setWorkingDirectory
```
protected void setWorkingDirectory(java.io.File dir)
```
    Set the working directory.
    
    Parameters:
    
    dir - The directory where the command will be executed
  - run
```
protected void run()
            throws java.io.IOException
```
    Check to see if a command needs to be executed and execute if needed.
    
    Throws:
    
    java.io.IOException - raised on errors performing I/O.
  - getExecString
```
protected abstract java.lang.String[] getExecString()
```
    return an array containing the command name and its parameters.
    
    Returns:
    
    exec string array.
  - parseExecResult
```
protected abstract void parseExecResult(java.io.BufferedReader lines)
                                 throws java.io.IOException
```
    Parse the execution result.
    
    Parameters:
    
    lines - lines.
    
    Throws:
    
    java.io.IOException - raised on errors performing I/O.
  - getEnvironment
```
public java.lang.String getEnvironment(java.lang.String env)
```
    Get an environment variable.
    
    Parameters:
    
    env - the environment var
    
    Returns:
    
    the value or null if it was unset.
  - getProcess
```
public java.lang.Process getProcess()
```
    get the current sub-process executing the given command.
    
    Returns:
    
    process executing the command
  - getExitCode
```
public int getExitCode()
```
    get the exit code.
    
    Returns:
    
    the exit code of the process
  - getWaitingThread
```
public java.lang.Thread getWaitingThread()
```
    get the thread that is waiting on this instance of Shell.
    
    Returns:
    
    the thread that ran runCommand() that spawned this shell or null if no thread is waiting for this shell to complete
  - isTimedOut
```
public boolean isTimedOut()
```
    To check if the passed script to shell command executor timed out or not.
    
    Returns:
    
    if the script timed out.
  - execCommand
```
public static java.lang.String execCommand(java.lang.String... cmd)
                                    throws java.io.IOException
```
    Static method to execute a shell command. Covers most of the simple cases without requiring the user to implement the Shell interface.
    
    Parameters:
    
    cmd - shell command to execute.
    
    Returns:
    
    the output of the executed command.
    
    Throws:
    
    java.io.IOException - raised on errors performing I/O.
  - execCommand
```
public static java.lang.String execCommand(java.util.Map<java.lang.String,java.lang.String> env,
                                           java.lang.String[] cmd,
                                           long timeout)
                                    throws java.io.IOException
```
    Static method to execute a shell command. Covers most of the simple cases without requiring the user to implement the Shell interface.
    
    Parameters:
    
    env - the map of environment key=value
    
    cmd - shell command to execute.
    
    timeout - time in milliseconds after which script should be marked timeout
    
    Returns:
    
    the output of the executed command.
    
    Throws:
    
    java.io.IOException - on any problem.
  - execCommand
```
public static java.lang.String execCommand(java.util.Map<java.lang.String,java.lang.String> env,
                                           java.lang.String... cmd)
                                    throws java.io.IOException
```
    Static method to execute a shell command. Covers most of the simple cases without requiring the user to implement the Shell interface.
    
    Parameters:
    
    env - the map of environment key=value
    
    cmd - shell command to execute.
    
    Returns:
    
    the output of the executed command.
    
    Throws:
    
    java.io.IOException - on any problem.
  - destroyAllShellProcesses
```
public static void destroyAllShellProcesses()
```
    Static method to destroy all running Shell processes. Iterates through a map of all currently running Shell processes and destroys them one by one. This method is thread safe
  - getAllShells
```
public static java.util.Set<Shell> getAllShells()
```
    Static method to return a Set of all Shell objects.
    
    Returns:
    
    all shells set.
  - getMemlockLimit
```
public static java.lang.Long getMemlockLimit(java.lang.Long ulimit)
```
    Static method to return the memory lock limit for datanode.
    
    Parameters:
    
    ulimit - max value at which memory locked should be capped.
    
    Returns:
    
    long value specifying the memory lock limit.

Class Shell

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

LOG

SYSPROP_HADOOP_HOME_DIR

ENV_HADOOP_HOME

ENV_HADOOP_OPTS

ENV_MAPR_JMX_OPTS

ENV_DEBUG_OPTS

WINDOWS_MAX_SHELL_LENGTH

WINDOWS_MAX_SHELL_LENGHT

USER_NAME_COMMAND

WindowsProcessLaunchLock

osType

WINDOWS

SOLARIS

MAC

FREEBSD

LINUX

OTHER

PPC_64

ENV_NAME_REGEX

SET_PERMISSION_COMMAND

SET_OWNER_COMMAND

SET_GROUP_COMMAND

LINK_COMMAND

READ_LINK_COMMAND

timeOutInterval

inheritParentEnv

WINUTILS

isSetsidAvailable

TOKEN_SEPARATOR_REGEX

Constructor Detail

Shell

Shell

Shell

Method Detail

isJava7OrAbove

isJavaVersionAtLeast

checkWindowsCommandLineLength

bashQuote

getGroupsCommand

getGroupsForUserCommand

getGroupsIDForUserCommand

checkUserExists

getUsersForNetgroupCommand

getGetPermissionCommand

getSetPermissionCommand

getSetPermissionCommand

getSetOwnerCommand

getSymlinkCommand

getReadlinkCommand

getCheckProcessIsAliveCommand

getSignalKillCommand

getEnvironmentVariableRegex

appendScriptExtension

appendScriptExtension

getRunScriptCommand

getHadoopHome

getQualifiedBin

getQualifiedBinPath

hasWinutilsPath

getWinUtilsPath

getWinUtilsFile

checkIsBashSupported

setEnvironment

setWorkingDirectory

run

getExecString

parseExecResult

getEnvironment

getProcess

getExitCode

getWaitingThread

isTimedOut

execCommand