环境变量

Julia 可以配置许多环境变量,一种常见的方式是直接配置操作系统环境变量,另一种更便携的方式是在 Julia 中配置。假设你要将环境变量 JULIA_EDITOR 设置为 vim,可以直接在 REPL 中输入 ENV["JULIA_EDITOR"] = "vim"(请根据具体情况对此进行修改),也可以将其添加到用户主目录中的配置文件 ~/.julia/config/startup.jl,这样做会使其永久生效。环境变量的当前值是通过执行 ENV["JULIA_EDITOR"] 来确定的。

The environment variables that Julia uses generally start with JULIA. If InteractiveUtils.versioninfo is called with the keyword verbose=true, then the output will list any defined environment variables relevant for Julia, including those which include JULIA in their names.

Note

Some variables, such as JULIA_NUM_THREADS and JULIA_PROJECT, need to be set before Julia starts, therefore adding these to ~/.julia/config/startup.jl is too late in the startup process. In Bash, environment variables can either be set manually by running, e.g., export JULIA_NUM_THREADS=4 before starting Julia, or by adding the same command to ~/.bashrc or ~/.bash_profile to set the variable each time Bash is started.

文件位置

JULIA_BINDIR

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

在默认情况下,可执行文件是指:

$JULIA_BINDIR/julia
$JULIA_BINDIR/julia-debug

全局变量 Base.DATAROOTDIR 是一个从 Sys.BINDIR 到 Julia 数据目录的相对路径。

$JULIA_BINDIR/$DATAROOTDIR/julia/base

上述路径是 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 是一个到配置文件目录的相对路径。在默认情况下,Julia 会在下列文件中搜索 startup.jl 文件(通过 Base.load_julia_startup()

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

例如,一个 Linux 安装包的 Julia 可执行文件位于 /bin/juliaDATAROOTDIR../shareSYSCONFDIR../etcJULIA_BINDIR 会被设置为 /bin,会有一个源文件搜索路径:

/share/julia/base

和一个全局配置文件搜索路径:

/etc/julia/startup.jl

JULIA_PROJECT

A directory path that indicates which project should be the initial active project. Setting this environment variable has the same effect as specifying the --project start-up option, but --project has higher precedence. If the variable is set to @. then Julia tries to find a project directory that contains Project.toml or JuliaProject.toml file from the current directory and its parents. See also the chapter on Code Loading.

Note

JULIA_PROJECT must be defined before starting julia; defining it in startup.jl is too late in the startup process.

JULIA_LOAD_PATH

The JULIA_LOAD_PATH environment variable is used to populate the global Julia LOAD_PATH variable, which determines which packages can be loaded via import and using (see Code Loading).

Unlike the shell PATH variable, empty entries in JULIA_LOAD_PATH are expanded to the default value of LOAD_PATH, ["@", "@v#.#", "@stdlib"] when populating LOAD_PATH. This allows easy appending, prepending, etc. of the load path value in shell scripts regardless of whether JULIA_LOAD_PATH is already set or not. For example, to prepend the directory /foo/bar to LOAD_PATH just do

export JULIA_LOAD_PATH="/foo/bar:$JULIA_LOAD_PATH"

If the JULIA_LOAD_PATH environment variable is already set, its old value will be prepended with /foo/bar. On the other hand, if JULIA_LOAD_PATH is not set, then it will be set to /foo/bar: which will expand to a LOAD_PATH value of ["/foo/bar", "@", "@v#.#", "@stdlib"]. If JULIA_LOAD_PATH is set to the empty string, it expands to an empty LOAD_PATH array. In other words, the empty string is interpreted as a zero-element array, not a one-element array of the empty string. This behavior was chosen so that it would be possible to set an empty load path via the environment variable. If you want the default load path, either unset the environment variable or if it must have a value, set it to the string :.

JULIA_DEPOT_PATH

The JULIA_DEPOT_PATH environment variable is used to populate the global Julia DEPOT_PATH variable, which controls where the package manager, as well as Julia's code loading mechanisms, look for package registries, installed packages, named environments, repo clones, cached compiled package images, configuration files, and the default location of the REPL's history file.

Unlike the shell PATH variable but similar to JULIA_LOAD_PATH, empty entries in JULIA_DEPOT_PATH are expanded to the default value of DEPOT_PATH. This allows easy appending, prepending, etc. of the depot path value in shell scripts regardless of whether JULIA_DEPOT_PATH is already set or not. For example, to prepend the directory /foo/bar to DEPOT_PATH just do

export JULIA_DEPOT_PATH="/foo/bar:$JULIA_DEPOT_PATH"

If the JULIA_DEPOT_PATH environment variable is already set, its old value will be prepended with /foo/bar. On the other hand, if JULIA_DEPOT_PATH is not set, then it will be set to /foo/bar: which will have the effect of prepending /foo/bar to the default depot path. If JULIA_DEPOT_PATH is set to the empty string, it expands to an empty DEPOT_PATH array. In other words, the empty string is interpreted as a zero-element array, not a one-element array of the empty string. This behavior was chosen so that it would be possible to set an empty depot path via the environment variable. If you want the default depot path, either unset the environment variable or if it must have a value, set it to the string :.

JULIA_HISTORY

REPL 历史文件中 REPL.find_hist_file() 的绝对路径。如果没有设置 $JULIA_HISTORY,那么 REPL.find_hist_file() 默认为

$(DEPOT_PATH[1])/logs/repl_history.jl

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,并且外部命令会直接被执行。

JULIA_EDITOR

InteractiveUtils.editor() 的返回值–编辑器,例如,InteractiveUtils.edit,会启动偏好编辑器,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,那么在 Windows 和 OS X 上会设置为 open,或者 /etc/alternatives/editor(如果存在的话),否则为 emacs

并行

JULIA_CPU_THREADS

改写全局变量 Base.Sys.CPU_THREADS,逻辑 CPU 核心数。

JULIA_WORKER_TIMEOUT

一个 Float64 值,用来确定 Distributed.worker_timeout() 的值(默认:60.0)。此函数提供 worker 进程在死亡之前等待 master 进程建立连接的秒数。

JULIA_NUM_THREADS

一个无符号 64 位整数(uint64_t),用来设置 Julia 可用线程的最大数。如果 $JULIA_NUM_THREADS 超过可用的物理 CPU 核心数,那么线程数设置为核心数。如果 $JULIA_NUM_THREADS 不是正数或没有设置,或者无法通过系统调用确定 CPU 核心数,那么线程数就会被设置为 1

Note

JULIA_NUM_THREADS 必须在启动 julia 前定义;在启动过程中于 startup.jl 中定义它为时已晚。

Julia 1.5

In Julia 1.5 and above the number of threads can also be specified on startup using the -t/--threads command line argument.

JULIA_THREAD_SLEEP_THRESHOLD

如果被设置为字符串,并且以大小写敏感的子字符串 "infinite" 开头,那么z自旋线程从不睡眠。否则,$JULIA_THREAD_SLEEP_THRESHOLD 被解释为一个无符号 64 位整数(uint64_t),并且提供以纳秒为单位的自旋线程睡眠的时间量。

JULIA_EXCLUSIVE

如果设置为 0 以外的任何值,那么 Julia 的线程策略与在专用计算机上一致:主线程在 proc 0 上且线程间是关联的。否则,Julia 让操作系统处理线程策略。

REPL 格式化输出

决定 REPL 应当如何格式化输出的环境变量。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 Julia REPL 章节。

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"),在终端中,输入应有的格式。

JULIA_ANSWER_COLOR

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

JULIA_STACKFRAME_LINEINFO_COLOR

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

调试和性能分析

JULIA_DEBUG

Enable debug logging for a file or module, see Logging for more information.

JULIA_GC_ALLOC_POOL, JULIA_GC_ALLOC_OTHER, JULIA_GC_ALLOC_PRINT

这些环境变量取值为字符串,可以以字符 ‘r’ 开头,后接一个由三个带符号 64 位整数(int64_t)组成的、以冒号分割的列表的插值字符串。这个整数的三元组 a:b:c 代表算术序列 a, a + b, a + 2*b, ... c

  • 如果是第 n 次调用 jl_gc_pool_alloc(),并且 n 属于 $JULIA_GC_ALLOC_POOL 代表的算术序列, 那么垃圾回收是强制的。
  • 如果是第 n 次调用 maybe_collect(),并且 n 属于 $JULIA_GC_ALLOC_OTHER 代表的算术序列,那么垃圾 回收是强制的。
  • 如果是第 n 次调用 jl_gc_alloc(),并且 n 属于 $JULIA_GC_ALLOC_PRINT 代表的算术序列,那么 调用 jl_gc_pool_alloc()maybe_collect() 的次数会 被打印。

如果这些环境变量的值以字符 ‘r' 开头,那么垃圾回收事件间的间隔是随机的。

Note

这些环境变量生效要求 Julia 在编译时带有垃圾收集调试支持(也就是,在构建配置中将 WITH_GC_DEBUG_ENV 设置为 1)。

JULIA_GC_NO_GENERATIONAL

如果设置为 0 以外的任何值,那么 Julia 的垃圾收集器将从不执行「快速扫描」内存。

Note

此环境变量生效要求 Julia 在编译时带有垃圾收集调试支持(也就是,在构建配置中将 WITH_GC_DEBUG_ENV 设置为 1)。

JULIA_GC_WAIT_FOR_DEBUGGER

如果设置为 0 以外的任何值,Julia 的垃圾收集器每当出现严重错误时将等待调试器连接而不是中止。

Note

此环境变量生效要求 Julia 在编译时带有垃圾收集调试支持(也就是,在构建配置中将 WITH_GC_DEBUG_ENV 设置为 1)。

ENABLE_JITPROFILING

如果设置为 0 以外的任何值,那么编译器将为即时(JIT)性能分析创建并注册一个事件监听器。

Note

此变量生效要求 Julia 编译时带有 JIT 性能分析支持,请使用

  • 英特尔的 VTune™ Amplifier(在构建配置中将 USE_INTEL_JITEVENTS 设置为 1),或
  • OProfile(在构建配置中将 USE_OPROFILE_JITEVENTS 设置为 1)。

JULIA_LLVM_ARGS

传递给 LLVM 后端的参数。