钩在终端上。 我可以在终端中运行命令之前调用方法吗？

Question

I am wanting to make a terminal app that stores information about files/directories. I want a way to keep the information if the file is moved or renamed.

What I thought I could do is have a function execute before any command is run. I found this:

http://www.twistedmatrix.com/users/glyph/preexec.bash.txt

But I was wondering if this would be a good way to go about it. Or should I do something else?

I would like to call that function from a C program whenever mv is entered I suppose.

Answer 1

If what you're trying to do is attach some sort of metadata to files, there's a much better supported way to do that -- extended attributes .

Another solution might be to use the file's inode number as an index into a database you maintain yourself.

Answer 2

Can you alias the mv command? in .profile or .bashrc

alias mv=/usr/bin/local/mymv

where mymv is a compiled executable that runs your C code function and calls /usr/bin/mv.

precmd and preeexec add some overhead to every bash script that gets run, even if the script never calls mv. The downside to alias is that it requires new code in /usr/local and if scripts or users employ /usr/bin/mv instead of mv it will not do what you want. Generally doing something like this often means there is a better way to handle the problem with some kind of service (daemon) or driver. Plus, what happens if your C code cannot correctly handle interesting input like

mv somefille /dev/null

Answer 3

If you want to run command each time after some command was executed in the terminal, just put the following in ~/.bashrc :

PROMPT_COMMAND="your_command;$PROMPT_COMMAND"

If you want your command to be executed each time before mv is executing, put the following in ~/.bashrc :

alias mv="your_script"

Make sure that your script will execute real mv if needed.

You can use inotify library to track filesystem changes. It's good solution, but once user remove file, it's already gone.

Answer 4

You might be able to make use of the DEBUG trap in Bash.

From man bash :

If a sigspec is DEBUG, the command arg is executed before every simple command, for command, case command, select command, every arithmetic for command, and before the first command executes in a shell function