Spark shell命令行

Question

我是Spark的新手并试图找出如何使用Spark shell。

查看Spark的网站文档，它没有显示如何创建目录或如何在spark shell中查看我的所有文件。如果有人能帮助我，我会很感激。

Answer 1

在此上下文中，您可以假设Spark shell只是普通Scala REPL，因此适用相同的规则。您可以使用:help获取可用命令的列表。

Welcome to
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    _\ \/ _ \/ _ `/ __/  '_/
   /___/ .__/\_,_/_/ /_/\_\   version 2.3.0
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Using Scala version 2.11.8 (OpenJDK 64-Bit Server VM, Java 1.8.0_151)
Type in expressions to have them evaluated.
Type :help for more information.

scala> :help
All commands can be abbreviated, e.g., :he instead of :help.
:edit <id>|<line>        edit history
:help [command]          print this summary or command-specific help
:history [num]           show the history (optional num is commands to show)
:h? <string>             search the history
:imports [name name ...] show import history, identifying sources of names
:implicits [-v]          show the implicits in scope
:javap <path|class>      disassemble a file or class name
:line <id>|<line>        place line(s) at the end of history
:load <path>             interpret lines in a file
:paste [-raw] [path]     enter paste mode or paste a file
:power                   enable power user mode
:quit                    exit the interpreter
:replay [options]        reset the repl and replay all previous commands
:require <path>          add a jar to the classpath
:reset [options]         reset the repl to its initial state, forgetting all session entries
:save <path>             save replayable session to a file
:sh <command line>       run a shell command (result is implicitly => List[String])
:settings <options>      update compiler options, if possible; see reset
:silent                  disable/enable automatic printing of results
:type [-v] <expr>        display the type of an expression without evaluating it
:kind [-v] <expr>        display the kind of expression's type
:warnings                show the suppressed warnings from the most recent line which had any

如上所示，您可以使用:sh调用shell命令。例如：

scala> :sh mkdir foobar
res0: scala.tools.nsc.interpreter.ProcessResult = `mkdir foobar` (0 lines, exit 0)

scala> :sh touch foobar/foo
res1: scala.tools.nsc.interpreter.ProcessResult = `touch foobar/foo` (0 lines, exit 0)

scala> :sh touch foobar/bar
res2: scala.tools.nsc.interpreter.ProcessResult = `touch foobar/bar` (0 lines, exit 0)

scala> :sh ls foobar
res3: scala.tools.nsc.interpreter.ProcessResult = `ls foobar` (2 lines, exit 0)

scala> res3.line foreach println
line   lines

scala> res3.lines foreach println
bar
foo

Answer 2

:q或:quit命令用于退出scala REPL。