环境变量

Julia 可以配置许多环境变量，可以以通常的操作系统方式，或者在 Julia 中以一种便携的方式。假设你要将环境变量 JULIA_EDITOR 设置为 vim，然后在 REPL 中输入 ENV["JULIA_EDITOR"] = "vim"，请根据具体情况进行此修改；或将其添加到用户主目录中的配置文件 ~/.julia/config/startup.jl，这会永久生效。一些环境变量的当前值是通过求 ENV["JULIA_EDITOR"] 的值来确定。

Julia 使用的环境变量通常以 JULIA 开头。如果 InteractiveUtils.versioninfo 调用时 verbose 等于 true，那么输出将列出与 Julia 相关的已定义环境变量，包括那些名称中包含 JULIA 的环境变量。

文件位置

JULIA_BINDIR

包含 Julia 可执行文件的目录的绝对路径会设置全局变量 Sys.BINDIR。$JULIA_BINDIR 如果没有设置，那么 Julia 在运行时确定 Sys.BINDIR 的值。

可执行文件是下列值中的一个

  1. $JULIA_BINDIR/julia
  2. $JULIA_BINDIR/julia-debug

在默认情况下。

全局变量 Base.DATAROOTDIR 确定一个从 Sys.BINDIR 到与 Julia 相关的数据目录的相对路径。路径

  1. $JULIA_BINDIR/$DATAROOTDIR/julia/base

确定 Julia 最初搜索源文件的路径。（通过Base.find_source_file()）。

同样，全局变量 Base.SYSCONFDIR 确定了一个到配置文件目录的相对路径。Julia 在下列文件中搜索 startup.jl 文件

  1. $JULIA_BINDIR/$SYSCONFDIR/julia/startup.jl
  2. $JULIA_BINDIR/../etc/julia/startup.jl

在默认情况下（通过 Base.load_julia_startup()）。

例如，一个 Linux 安装包的 Julia 可执行文件位于 /bin/julia，DATAROOTDIR 为 ../share，SYSCONFDIR 为 ../etc，JULIA_BINDIR 会被设置为 /bin，会有一个源文件搜索路径

  1. /share/julia/base

和一个全局配置搜索路径

  1. /etc/julia/startup.jl

JULIA_LOAD_PATH

一个由被附加到变量 LOAD_PATH 的绝对路径组成的分隔列表（在类 Unix 系统中，路径分隔符为 :；在 Windows 系统中，路径分隔符为 ;）。LOAD_PATH 变量是 Base.require 和 Base.load_in_path() 寻找代码的地方。它默认为绝对路径 $JULIA_HOME/../share/julia/stdlib/v$(VERSION.major).$(VERSION.minor)，例如，在 0.7 版本的 Julia 上，其中系统为 Linux 且 Julia 可执行文件为 /bin/julia，LOAD_PATH 将默认为 /share/julia/stdlib/v0.7。

JULIA_HISTORY

REPL 历史文件中 REPL.find_hist_file() 的绝对路径。如果 $JULIA_HISTORY 没有定义，REPL.find_hist_file() 默认为

  1. $HOME/.julia/logs/repl_history.jl

JULIA_PKGRESOLVE_ACCURACY

A positive Int that determines how much time the max-sum subroutine MaxSum.maxsum() of the package dependency resolver will devote to attempting satisfying constraints before giving up: this value is by default 1, and larger values correspond to larger amounts of time.

Suppose the value of $JULIA_PKGRESOLVE_ACCURACY is n. Then

  • the number of pre-decimation iterations is 20*n,
  • the number of iterations between decimation steps is 10*n, and
  • at decimation steps, at most one in every 20*n packages is decimated.

    外部应用

JULIA_SHELL

Julia 用来执行外部命令的 shell 的绝对路径（通过 Base.repl_cmd()）。默认为环境变量 $SHELL，如果 $SHELL 未设置，则为 /bin/sh。

Note

在 Windows 上，此环境变量将被忽略，并且外部命令直接被执行。

JULIA_EDITOR

由 InteractiveUtils.editor() 返回的编辑器并被使用，例如，InteractiveUtils.edit，引用首选编辑器的命令，比如 vim。

$JULIA_EDITOR 优先于 $VISUAL，而后者优先于 $EDITOR。如果这些环境变量都没有设置，那么编辑器在 Windows 和 OS X 上设置为 open，或者 /etc/alternatives/editor 如果其存在，否则为 emacs。

Parallelization

JULIA_CPU_THREADS

Overrides the global variable Base.Sys.CPU_THREADS, the number of logical CPU cores available.

JULIA_WORKER_TIMEOUT

A Float64 that sets the value of Base.worker_timeout() (default: 60.0). This function gives the number of seconds a worker process will wait for a master process to establish a connection before dying.

JULIA_NUM_THREADS

An unsigned 64-bit integer (uint64_t) that sets the maximum number of threads available to Julia. If $JULIA_NUM_THREADS exceeds the number of available physical CPU cores, then the number of threads is set to the number of cores. If $JULIA_NUM_THREADS is not positive or is not set, or if the number of CPU cores cannot be determined through system calls, then the number of threads is set to 1.

JULIA_THREAD_SLEEP_THRESHOLD

If set to a string that starts with the case-insensitive substring "infinite", then spinning threads never sleep. Otherwise, $JULIA_THREAD_SLEEP_THRESHOLD is interpreted as an unsigned 64-bit integer (uint64_t) and gives, in nanoseconds, the amount of time after which spinning threads should sleep.

JULIA_EXCLUSIVE

If set to anything besides 0, then Julia's thread policy is consistent with running on a dedicated machine: the master thread is on proc 0, and threads are affinitized. Otherwise, Julia lets the operating system handle thread policy.

REPL 格式化

决定 REPL 输出在终端中应当如何被格式化的环境变量。通常，这些变量应当被设置为 ANSI 终端转义序列。Julia 提供了具有相同功能的高级接口：请参阅 The Julia REPL。

JULIA_ERROR_COLOR

Base.error_color()（默认值：亮红，"\033[91m"），errors 在终端中的格式。

JULIA_WARN_COLOR

Base.warn_color()（默认值：黄，"\033[93m"），warnings 在终端中的格式。

JULIA_INFO_COLOR

Base.info_color()（默认值：青，"\033[36m"），info 在终端中的格式。

JULIA_INPUT_COLOR

Base.input_color()（默认值：标准，"\033[0m"），输入在终端中的格式。

JULIA_ANSWER_COLOR

Base.answer_color()（默认值：标准，"\033[0m"），输出在终端中的格式。

JULIA_STACKFRAME_LINEINFO_COLOR

Base.stackframe_lineinfo_color()（默认值：粗体，"\033[1m"），堆栈跟踪时行信息在终端中的格式。

JULIA_STACKFRAME_FUNCTION_COLOR

Base.stackframe_function_color()（默认值：粗体，"\033[1m"），堆栈跟踪期间函数调用在终端中的形式。

Debugging and profiling

JULIA_GC_ALLOC_POOL, JULIA_GC_ALLOC_OTHER, JULIA_GC_ALLOC_PRINT

If set, these environment variables take strings that optionally start with the character 'r', followed by a string interpolation of a colon-separated list of three signed 64-bit integers (int64_t). This triple of integers a:b:c represents the arithmetic sequence a, a + b, a + 2*b, … c.

  • If it's the nth time that jl_gc_pool_alloc() has been called, and n belongs to the arithmetic sequence represented by $JULIA_GC_ALLOC_POOL, then garbage collection is forced.
  • If it's the nth time that maybe_collect() has been called, and n belongs to the arithmetic sequence represented by $JULIA_GC_ALLOC_OTHER, then garbage collection is forced.
  • If it's the nth time that jl_gc_collect() has been called, and n belongs to the arithmetic sequence represented by $JULIA_GC_ALLOC_PRINT, then counts for the number of calls to jl_gc_pool_alloc() and maybe_collect() are printed.
    If the value of the environment variable begins with the character 'r', then the interval between garbage collection events is randomized.

Note

These environment variables only have an effect if Julia was compiled with garbage-collection debugging (that is, if WITH_GC_DEBUG_ENV is set to 1 in the build configuration).

JULIA_GC_NO_GENERATIONAL

If set to anything besides 0, then the Julia garbage collector never performs "quick sweeps" of memory.

Note

This environment variable only has an effect if Julia was compiled with garbage-collection debugging (that is, if WITH_GC_DEBUG_ENV is set to 1 in the build configuration).

JULIA_GC_WAIT_FOR_DEBUGGER

If set to anything besides 0, then the Julia garbage collector will wait for a debugger to attach instead of aborting whenever there's a critical error.

Note

This environment variable only has an effect if Julia was compiled with garbage-collection debugging (that is, if WITH_GC_DEBUG_ENV is set to 1 in the build configuration).

ENABLE_JITPROFILING

If set to anything besides 0, then the compiler will create and register an event listener for just-in-time (JIT) profiling.

Note

This environment variable only has an effect if Julia was compiled with JIT profiling support, using either

  • Intel's VTune™ Amplifier (USE_INTEL_JITEVENTS set to 1 in the build configuration), or
  • OProfile (USE_OPROFILE_JITEVENTS set to 1 in the build configuration).

    JULIA_LLVM_ARGS

Arguments to be passed to the LLVM backend.

JULIA_DEBUG_LOADING

If set, then Julia prints detailed information about the cache in the loading process of Base.require.

原文: https://juliacn.github.io/JuliaZH.jl/latest/manual/environment-variables/