Little one liners you always need

ip – show / manipulate routing, network devices, interfaces and tunnels

ip addr
ip route show

du – estimate file space usage

du --max-depth=1 --human-readable --one-file-system Documents/
du -hxd 1 Documents/

rsync – a fast, versatile, remote (and local) file-copying tool

rsync -avz --update -e ssh --progress --delete leopardb@neptune:/home/leopardb/Documents/ /home/leopardb/Documents/ --dry-run
rsync -avz --update -e ssh --progress --delete leopardb@neptune:/home/leopardb/Documents/ /home/leopardb/Documents/


For some reason, this is not the default, but to connect to any reasonably recent SMB server, you must pass the -m SMB3 argument, like:

smbclient -m SMB3 -L mycomp -U myuser -W MYDOMAIN
smbclient -m SMB3 //mycomp/sharedfolder -U myuser -W MYDOMAIN

To send an email in one line

Sending it to root, to make sure the redirection works.

In my case, using postfix, the right email address is in /etc/aliases

echo -e "\\nSubject:Test Email - can delete \n\n Just a test, did it come through ?\n" | sendmail root