Linux, Bash: ./?

[mikeshn]

I always wanted to ask: Why some commands I must start as ./command and some just command?

I think that if I type just command it should be in my path when I type ./command not in my path. Correct?

Example:

[root@localhost sbin]# ./iptables -L
Chain INPUT (policy ACCEPT)
target prot opt source destination
RH-Lokkit-0-50-INPUT all -- anywhere anywhere

[root@localhost sbin]# iptables -L
bash: iptables: command not found
[root@localhost sbin]#


./iptables -> works
iptables -> error

Thanks
M.S.

 

[n0cmonkey]

. is the current directory. So ./command is the command in the current working directory, where as the shell would look through your $PATH (in order) and execute the first command (the command you typed in, not just any command 😉) it finds. If you have . in your $PATH you should be fine, unless there is a command with the same name earlier in your $PATH.

 

[Buddha Bart]

If you have . in your $PATH

Some people consider this a security vulnerability. In and of itself its not, but when combined with some social enginiering it is often used it a local-attack. Of course this probably isn't that big a deal especially if you don't have lots of users on your system, but just for good measure at least make sure to keep "." out of root's path.

bart

 

[n0cmonkey]

Originally posted by: Buddha Bart

If you have . in your $PATH

Some people consider this a security vulnerability. In and of itself its not, but when combined with some social enginiering it is often used it a local-attack. Of course this probably isn't that big a deal especially if you don't have lots of users on your system, but just for good measure at least make sure to keep "." out of root's path.

bart

I actually have . in root's $PATH. It rarely gets used though, because I am fairly used to using the ./.