这个bash脚本如何导致无限循环？(How is this bash script resulting in an infinite loop?)

 从一些谷歌搜索（我不是任何bash专家）我能够组合一个bash脚本，允许我运行测试套件并在运行时在底部输出状态栏。 它通常需要大约10个小时，状态栏告诉我通过了多少次测试以及失败了多少次。 
 
 它有时很好用，但偶尔我会遇到一个无限循环，这很糟糕（mmm-kay？）。 这是我正在使用的代码： 
 
#!/bin/bash
WHITE="\033[0m"
GREEN="\033[32m"
RED="\033[31m"

(run_test_suite 2>&1) | tee out.txt |
while IFS=read -r line;
do
    printf "%$(tput cols)s\r" " ";
    printf "%s\n" "$line";

    printf "${WHITE}Passing Tests: ${GREEN}$(grep -c passed out.txt)\t"         2>&1;
    printf "${WHITE}Failed Tests: ${RED}$(   grep -c FAILED out.txt)${WHITE}\r" 2>&1;
done
 
 当我遇到这个错误时会发生什么，我会有一个无限重复的错误信息，导致日志文件（ out.txt ）变成一些兆字节的怪物（我认为它进入了GB的一次）。 这是一个重复的示例错误（每组之间有四行空格）： 
 
warning caused by MY::Custom::Perl::Module::TEST_FUNCTION
print() on closed filehandle GEN3663 at /some/CPAN/Perl/Module.pm line 123.
 
 我已经尝试取出2>&1重定向，我尝试while IFS=read -r line;更改while IFS=read -r line; while read -r line; ，但我一直在无限循环。 更奇怪的是这似乎发生在大多数时间，但有时我完成了长测试套件没有任何问题。 
 
 编辑 ： 
 
 我写这篇文章的原因是从黑白测试套件升级到颜色编码的测试套件（因此是ANSI代码）。 以前，我会使用测试套件 
 
run_test_suite > out.txt 2>&1 &
watch 'grep -c FAILED out.txt; grep -c passed out.txt; tail -20 out.txt'
 
 以这种方式运行它会从Perl获得相同的警告，但是将其打印到文件并继续运行，而不是陷入无限循环。 使用手表，也打印[32m而不是实际将文本渲染为绿色的东西。 

From some Googling (I'm no bash expert by any means) I was able to put together a bash script that allows me to run a test suite and output a status bar at the bottom while it runs. It typically takes about 10 hours, and the status bar tells me how many tests passed and how many failed.
 
It works great sometimes, however occasionally I will run into an infinite loop, which is bad (mmm-kay?). Here's the code I'm using:
 
#!/bin/bash
WHITE="\033[0m"
GREEN="\033[32m"
RED="\033[31m"

(run_test_suite 2>&1) | tee out.txt |
while IFS=read -r line;
do
    printf "%$(tput cols)s\r" " ";
    printf "%s\n" "$line";

    printf "${WHITE}Passing Tests: ${GREEN}$(grep -c passed out.txt)\t"         2>&1;
    printf "${WHITE}Failed Tests: ${RED}$(   grep -c FAILED out.txt)${WHITE}\r" 2>&1;
done
 
What happens when I encounter the bug is I'll have an error message repeat infinitely, causing the log file (out.txt) to become some multi-megabyte monstrosity (I think it got into the GB's once). Here's an example error that repeats (with four lines of whitespace between each set):
 
warning caused by MY::Custom::Perl::Module::TEST_FUNCTION
print() on closed filehandle GEN3663 at /some/CPAN/Perl/Module.pm line 123.
 
I've tried taking out the 2>&1 redirect, and I've tried changing while IFS=read -r line; to while read -r line;, but I keep getting the infinite loop. What's stranger is this seems to happen most of the time, but there have been times I finish the long test suite without any problems.
 
EDIT:
 
The reason I'm writing this is to upgrade from a black & white test suite to a color-coded test suite (hence the ANSI codes). Previously, I would run the test suite using
 
run_test_suite > out.txt 2>&1 &
watch 'grep -c FAILED out.txt; grep -c passed out.txt; tail -20 out.txt'
 
Running it this way gets the same warning from Perl, but prints it to the file and moves on, rather than getting stuck in an infinite loop. Using watch, also prints stuff like [32m rather than actually rendering the text as green.

原文：https://stackoverflow.com/questions/14991148