执行>> Julia程序中的shell运算符 [英] Executing the >> shell operator from a Julia program

问题描述

我试图使用反引号从Julia内部添加文件

I was trying to append a file from inside Julia using backticks

run(`cat file2 >> file1`)

但这是行不通的.似乎>>运算符无法正确解释.有什么办法可以通过管道或其他技巧来做到这一点?

but this doesn't work. It seems the >> operator can't be interpreted correctly. Is there some way to do this with a pipeline or other trick?

推荐答案

以下内容将字符串作为文字shell脚本运行，从而规避了Julia为您设置的安全性:

The following will run a string as a literal shell script, circumventing the safeties Julia sets up for you:

script = "cat file2 >> file1"
run(`sh -c $script`)

假设已设置file1和file2的参数，则以下内容更安全(不易受到外壳注入攻击，因为它会从脚本文本中带外通过file1和file2): /p>

Assuming that file1 and file2 are parameterized, the following is a safer equivalent (not prone to shell injection attacks, as it passes file1 and file2 out-of-band from script text):

script = "cat \"\$1\" >> \"\$2\""
source = "file1"
dest = "file2"
run(`sh -c $script _ $source $dest`)

这会将_传递为$ 0，将file1传递为$1，并且将file2传递为$2.

This passes _ as $0, file1 as $1, and file2 as $2.

最后，要完全避免使用shell，请指定stdout=作为文件句柄:

Finally, to avoid a shell altogether, specify stdout= to be your file handle:

source = "file1"
dest = "file2"
run(pipeline(`cat $source`, stdout=open(dest, "a")))

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