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what does this command mean?

install usb_storage \
wall "usb storage devices not allowed"  \
&& /bin/false

what does && mean? what happen with single & or without & ?

why /bin/false?

Thanks.
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binary_1001010
Asked:
binary_1001010
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2 Solutions
 
xDamoxCommented:
Hi,

The following just means:

install usb_storage wall "usb storage devices not allowed"  && /bin/false

The \ mean the command is going to go onto the next line the && means and so once its
ran

install usb_storage wall "usb storage devices not allowed"

it will then execute the following command:

/bin/false

If you wanted you could do run this command first:

install usb_storage wall "usb storage devices not allowed"

ten run this command:

/bin/false
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pjedmondCommented:
install usb_storage wall "usb storage devices not allowed"  && /bin/false

Means try to install the 'usb_storage', but in the case of failure

wall "usb storage devices not allowed" - send this message to everyone logged in

 && /bin/false - && is a logical AND, so as well as telling everyone that the usb storage is not allowed, it will return a value of 'false' indicating failure, from the command.
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binary_1001010Author Commented:
is it compulsory to have double &?  and i use single & ? wat will happen?

Thanks.
0
 
xDamoxCommented:
Hi,

Yes the && is compulsory if you step into the programming world the && is compulsory. If you do bash programming
too you use the && thats where the && comes from.
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pjedmondCommented:
A single & will create a 'background' process, but in this scenario will make the command syntactically illegal, and will respond with an error.
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