Why does my shell script create a file named pipe?

问题:

I have this simple set up:

pwd
/home/abc/pipetest

ls
mydir  pipetest.sh

Now I do:

 ./pipetest.sh

And then I get

  ls
  file.tar.bz2  mydir  pipe  pipetest.sh

My question is: Why did the file named pipe get created? It contains some characters that could not be seen using vi. What's going on?

pipetest.sh contains:

#!/bin/sh

directory_name=mydir
tar cf pipe $directory_name
bzip2 -c < pipe > file.tar.bz2

回答1:

tar cf pipe $directory_name writes the tar file to a file named pipe.

What you want to do is using the actual pipe:

tar c $directory_name | bzip2 > file.tar.bz2

Or simply use

tar cjf file.tar.bz2 $directory_name

回答2:

tar -cf pipe

creates a tar file named "pipe" in the current directory.