Use of && & || in Bash scripts (was: Using Ubuntu absolves the user of personal responsibility (no I'm guilty) and can you help me with my problem?)

[Alexander Skwar]

· José Paulo Matafome Oleiro <matafomeoleiro at gmail.com>:

> $ sudo mount -o loop -t iso9660 /isofile /mountpoint && sudo apt-get
> install package_name && sudo mount -o loop -t
> iso9660 /isofile /mountpoint
> (this can mount the iso file at the end of the process again, should it
> work, or I need to replace && with || I don't know maybe you can help me
> with this out

&& means "do, if successful"
|| means "do, if not successful"

Thus your command line means:

        mount isofile
        if that's successful, do apt-get
        if that (ie. apt-get) is successful, do mount isofile

&& and || are short forms for "if". Your command could also be written
as:

        if sudo mount -o loop -t iso9660 /isofile /mountpoint; then
                if sudo apt-get install package_name; then
                        sudo mount -o loop -t iso9660 /isofile /mountpoint
                fi
        fi

IMO, that's easier to understand.

The "BASH Programming HowTo" might be of interest.  Google for it, 
"you moron" ;)

Alexander Skwar
-- 
Unsere Handlungen sind nicht so lasterhaft wie unsere Absichten.
                -- Luc de Clapiers Vauvenargues (Reflexionen und Maximen)