无法从bash脚本中获取带有空格的SCP路径吗？

Question

I have a bash script which generates an SCP command to execute. The relevant parts of the code look like this:

echo $COPY_CMD
$COPY_CMD

My output looks like this:

rascher@localhost:~/Desktop/video_final$ ./xfervids.sh 
scp "/media/My Book/PhotosVideos/Videos/18May2008Download/SD_VIDEO/PRG001/MOV056.MOD" rascher@192.168.1.101:./video_working/
rascher@192.168.1.101's password: 
"/media/My: No such file or directory
Book/PhotosVideos/Videos/18May2008Download/SD_VIDEO/PRG001/MOV056.MOD": No such file or directory

However, when I take line 2 of my output: scp "/media/... , copy it, and paste it into the terminal, it works.

What am I doing wrong? I have tried escaping the space in "My Book" ( "My\\ Book" ), putting two \\ characters rather than one ( "My\\\\ Book" ) but I can't get this to behave consistently. Help?

Answer 1

You have to be excruciatingly careful when there are spaces in the path names.

In the context, you probably need:

eval $COPY_CMD

You don't need quotes around the variable this time.

Answer 2

You should read this discussion of how and why to avoid putting commands in variables and this discussion of the security implications of eval .

One reason you may want to use variables in this way is to log or display the actions taken by a script. Problems occur with being able to properly quote or escape spaces, etc., as you have discovered. One way to do what you may want is to use set -x and set +x to turn this type of output on and off at various points in your script.