What to do when a command isn't found?

jdow jdow at earthlink.net
Thu Jul 6 19:21:20 UTC 2006


From: "nigel henry" <cave.dnb at tiscali.fr>

> On Thursday 06 July 2006 18:58, Timothy Alberts wrote:
>> So I get this every now and then and haven't found a smooth method of
>> dealing with it.  I have my desktop upgraded from FC4 to FC5 and the
>> command 'ifconfig' comes back with 'bash: ifconfig: command not found.'
>> Additionally, I have been through tutorials on the web and different
>> books on running commands that more often than not, the bash shell comes
>> back with the same message.
>>
>> My first question is, are the shell commands and features standardized
>> somewhere so that I know what commands I can expect to have no matter
>> what machine I'm sitting at or what type of installation I have?  My
>> second question is, if these commands are supposed to be there, but the
>> shell comes back and says they aren't, what is the procedure for finding
>> the commands or installing the packages required for them?
>>
>> I understand the 'which xxx' command will tell me the location of the
>> executable that is being used when I call a command.  However it doesn't
>> help me find a missing command.  I also understand that typically shell
>> commands are in /bin /usr/bin /usr/local/bin among others.  If it helps,
>> when I type 'which ifconfig' the following is the result:
>>
>> /usr/bin/which: no ifconfig in
>> (/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/bin:/usr/bin:/bin:
>> /usr/X11R6/bin:/home/talberts/bin)
>>
>> Sorry these are fairly general questions so if it's easier to just focus
>> on the 'ifconfig' command that would be helpful.  Thank you for any
>> response.
> 
> Hi Tim. Just for a start ifconfig is in /sbin/ifconfig . Darned annoying isn't 
> it.

The /sbin and /usr/sbin directories are generally commands that users
should not use and which may not work at all for users. It is a basic
part of the security of the system. Unfettered access to ifconfig gives
a really nice way to perform nastiness on your system by bringing up
or down various interfaces. It's somewhat handy if commands users are
not expected to use are not on the user's path.

{^_^}




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