rsync reminder

$ rsync -a a b <==> b/a/foo
$ rsync -a a/ b <==> b/foo
destination (b) <==> destination/ (b/)

If you need to pass parameters to rsync-over-ssh, then includ them in ‘ – as in:

$ rsync -ave ‘ssh -i /home/netfortius/.ssh/remote_private_dsa’ user_at_remote@remote_system:/path/ ./local/path


VM printing – Linux (host) & Windows (guest)

# lsof |grep lp (lp0)
– for VM guest (Windows) to print, on host run:
# rmmod lp
NOTE: may need to stop cups daemon on the host, first
– for Linux (host) to print:
# modprobe lp
# chown <user> /dev/parport0
# chgrp lp /dev/parport0

postfix misc. commands

# postqueue -p = list messages
# postsuper -d <msg> = delete
# postsuper -d ALL = delete all
# postsuper -h <msg> = hold
# postsuper -H <msg> = put back in the queue
# postsuper -r ALL = requeue ALL messages
# postcat -q <msg> = display
# mailq = display queue

terminal shortcuts

Control-A = goto beginning of the line
Control-E = goto to the end of the line
ESC B = goto previous word
ESC F = goto next word
Control-H / backspace = delete previous character
Control-D = delete next character
ESC D = cut next word
ESC Backspace = cut previous word
Control-K = cut to end of line
Control-Y = paste last cut text
Control-L = redraw screen
Control-Q = resume output (XON)
Control-S = pause output (XOFF)
Control-C = stop current program
Control-Z = suspend current program
Up-arrow = show previously run command

tunneling over SSH


$ ssh -N -f -L <local_port>:<end_server>:<end_port> user@ssh_intermediary_server

NOTE: if using auth. w/keys and no passwd, the last part (user@…) is not needed


$ ssh -f -N -L my_home_machine -L my_home_machine

allows me to use the email client on a laptop, pointing to localhost:8025 for SMTP services, and localhost:8110 for POP3 services associated with my Comcast account, w/out traversing “foreign” networks with clear text credentials.

If moving between places, I would need tostop and restart the process. This could be as simple as:

$ ps aux |grep ssh |grep -v grep |awk ‘{print $2}’ |xargs kill -9

SSH with keys

Execute on local host, under user’s pwd:

$ mkdir -p ~/.ssh
$ chmod 700 ~/.ssh
$ cd ~/.ssh
$ ssh-keygen -t dsa

Copy the public key to the remote host

$ scp -p remoteuser@remotehost:
Password: *********

Log into remote host and install public key

$ ssh remoteuser@remotehost
Password: ********

remotehost$ mkdir -p ~/.ssh
remotehost$ chmod 700 ~/.ssh
remotehost$ cat >> ~/.ssh/authorized_keys
remotehost$ chmod 600 ~/.ssh/authorized_keys
remotehost$ mv ~/.ssh
remotehost$ logout

“Political Correctness” and English Grammar

My all time favorite comment, regarding usage of indefinite pronouns, appears at the bottom of this article:

“All right, I’m only going to say this once: ‘He’ is the singular indefinite pronoun in English (“if a person drinks too much, he will likely experience a hangover”). ‘He’ also happens to be the masculine personal pronoun.

‘She’ is the singular pronoun of personification in English (“if England fails to advance America’s foreign-policy ambitions, she will suffer terrible consequences”). ‘She’ also happens to be the feminine personal pronoun.

Confusing the two exhibits not a warm-and-fuzzy concern for the inclusion of women so much as a writer’s or speaker’s ignorance. Using the feminine personal pronoun as an indefinite article is as moronic as using the masculine personal pronoun for personification. Thus the captain greets us: “Welcome to my ship. Isn’t he splendid?”

Give it up, people. It’s not thoughtful; it’s just illiterate.”