Python Fabric，为什么 grep 使用 [] 失败

Question

我想知道为什么我在使用 [] 执行 grep 时遇到 fatal error ，在这里寻找逻辑。

工作:

    In [37]: run("""ps aux | grep "grunt" """)
    [worker2] run: ps aux | grep "grunt" 
    [worker2] out: root     21414  0.0  0.0  16476  5632 pts/0    Ss+  03:10   0:00 /bin/bash -l -c ps aux | grep "grunt" 
    [worker2] out: root     21475  0.0  0.0  11752   884 pts/0    S+   03:10   0:00 grep grunt
    [worker2] out: 

    Out[37]: 'root     21414  0.0  0.0  16476  5632 pts/0    Ss+  03:10   0:00 /bin/bash -l -c ps aux | grep "grunt" \r\nroot     21475  0.0  0.0  11752   884 pts/0    S+   03:10   0:00 grep grunt'

不工作:

    In [38]: run("""ps aux | grep "[g]runt" """)
    [worker2] run: ps aux | grep "[g]runt" 

    Fatal error: run() received nonzero return code 1 while executing!

    Requested: ps aux | grep "[g]runt" 
    Executed: /bin/bash -l -c "ps aux | grep \"[g]runt\" "

    Aborting.
    An exception has occurred, use %tb to see the full traceback.

    SystemExit: run() received nonzero return code 1 while executing!

知道为什么第二节不起作用吗？

Answer 1

为了避免 grep 返回 exit 1，请如下所示:

grep "[g]runt" | tee

这是因为 grep 在使用方括号时实际上找不到任何内容(当 grunt 真正运行时，它应该可以工作，尝试一下)