My cheatsheet of random computer-related stuff.
Bootable clone of a macOS drive (Big Sur, Monterey)
sudo asr restore --no-personalization --source / --target /Volumes/xyz --erase --verbose
See www.prosofteng.com/blog/how-to-create-a-bootable-external-hard-drive-clone-on-macos
GNU Fortran compiler
MacPorts
port selfupdate port outdated port upgrade outdated port installed inactive port uninstall inactive port uninstall inactive and not <portname> port echo depends:<portname> port dependents <portname> port installed requested and rdependentof:<portname> port installed requested port echo leaves port setrequested <portname> port unsetrequested <portname> port uninstall --follow-dependencies leaves port select --list python port select --set python python34
Anaconda
conda update -n root conda … update conda itself conda update --all … update all packages in the current environment
FEniCS in Anaconda
conda activate fenicsproject
conda deactivate
FEniCS in Docker
fenicsproject run
FEniCS
fenicsproject.org
fenics-handson.readthedocs.io … FEniCS hands-on by Jan Blechta, Roland Herzog, Jaroslav Hron, Gerd Wachsmuth
fenics-solid-tutorial.readthedocs.io … FEniCS hand-on by Jaroslav Schmidt, Petr Pelech, Mark Dostalík, Jiří Malík
Password-less ssh
First generate an authentication key on the host you intend to run the code from:
% ssh-keygen -t rsa
During this procedure you will be prompted for a passphrase – set one or leave empty (no passphrase). Then send the contents of the file “~/.ssh/id_rsa.pub” created by the previous command to one of the networked Linux machines you wish to use:
% cat ~/.ssh/id_rsa.pub | ssh user@machine2 'cat >> .ssh/authorized_keys'
If the file “~/.ssh/authorized_keys” doesn’t exist, create it.
Now password-less ssh to the workstation should work.
screen (e.g., here)
Start screen: screen
Exit screen: exit
Detach from screen (it keeps running in the background): Ctrl+A+D
Return to screen screen -r
If multiple screens running, then screen [-d] -r [pid.]tty.host (list of screens from running screen -r)
Command line to reduce PDF file size
gs -sDEVICE=pdfwrite -dPDFSETTINGS=/screen -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.pdf input.pdf
Gnuplot examples
set terminal png set output 'file.png' plot 'horiz_avg.0' using 2:1 with lines, '' using 6:1 w l, '' u 7:1 w l
Backup using rsync
Backup of home directory:
rsync -Pavvz --delete /Users/johndoe/* /Volumes/Backup/Users/johndoe/
Backup of home directory with exclusion of a directory:
rsync -Pavvz --delete --delete-excluded --exclude 'VirtualBox VMs' /Users/johndoe/* /Volumes/Backup/Users/johndoe/
Backup that involves ssh:
rsync -Pavz -e ssh --delete johndoe@machine:~/* /Volumes/Backup/Machine/
-P = --partial --progress keep partially transferred files, show progress-a = -rlptgoD archive mode (recursive, copy symbolic links as they are, preserve permission, time, group, owner, devices)-v = --verbose increases verbosity, -vv talks a lot-z = --compress compresses the data on transfer--delete delete files on receiver, that do not exist on sender
Bootable backup (from www.bombich.com/mactips/image.html)
Ditto is a command-line utility that ships with Mac OS X. Ditto preserves permissions when run as root and preserves resource forks by default. Ditto can be used to clone your system with the following step:
sudo ditto -X / /Volumes/Backup
rsync can be used to make a bootable clone as well. In addition to basic file copying, rsync also offers the ability to synchronize the source and target volumes — it can copy only the items that have changed, thus subsequent clones, or backups, are much faster. The syntax is pretty easy:
sudo rsync -xrlptgoEv --progress --delete / /Volumes/Backup
That will backup your entire drive, deleting anything from the target that is not on the source drive (synchronizing, that is). Rsync also preserves resource forks (that’s what the “E” argument is for) and will give you a bootable backup just as well as ditto. Learn more about using rsync to regularly backup your drive to a remote machine.
Linux tools
sort, uniq, tr, wc, xargs
New Linux X server restart key combination: AltGr-PrintScreen-K
ssh tunneling
Example: need to connect to lyon through praha
1. Edit /etc/hosts and change
127.0.0.1 localhost
to
127.0.0.1 localhost lyon.colorado.edu
2. Edit .ssh/config and put there
Host lyon.colorado.edu port 4444
3. Run
ssh -X -f johndoe@praha.colorado.edu -N -L 4444:lyon.colorado.edu:22
4. Then run
ssh -X johndoe@lyon.colorado.edu
(see docs.cs.byu.edu/general/ssh_tunnels.html)
ImageMagick
Swapping colors:
convert input.jpg -fill to_color -opaque from_color output.jpg
Make a color tranparent (note jpeg’s cannot have transparent bg, need to use gif or png):
convert input.jpg -transparent color output.gif
Mercurial (mercurial.selenic.com)
~/.hgrc
$ hg init project
$ cd project
$ echo 'print("Hello")' > hello.py
$ hg add
$ hg forget
$ hg commit OR $ hg commit -m 'message' NOTE commit = ci
$ hg log
$ hg status
$ hg diff
$ hg cp a b
$ hg mv a b
$ hg log -p -r 3
$ hg update 1 NOTE update = up
$ hg update tip
$ hg update null
$ hg identify -n
$ hg merge
$ hg resolve --list
$ hg resolve conflicting_file
$ hg resolve --mark conflicting_file
...
Paper sizes and printing
8.5×11 “letter” | 8.5×14 “legal” | 11×17 “tabloid” | 17×11 “ledger”
xdvi -paper letter|legal|tabloid|ledger file.dvi
dvips -t letter|a4 file.dvi
ps2pdf file.ps
dvipdfm -p a4 file.dvi
a2ps --medium=A4 -o file.ps file.txt
a2ps -M A4 -o file.ps file.txt
pdflatex creates pdf of correct size corresponding to specification in geometry setting.
Linux double-sided printing long-edge binding:
lpr -Palenka -o Duplex=DuplexNoTumble file.pdf
Linux double-sided printing short-edge binding:
lpr -Palenka -o Duplex=DuplexTumble file.pdf
DVDs
Handbrake or Mac The Ripper
Strings in Mail
Automatic strings in reply messages, forwarded messages, etc… – edit file:
/System/Library/Frameworks/Message.framework/Versions/B/Resources/English.lproj/Delayed.strings
HP Printer WiFi setup
First part following this YouTube video: www.youtube.com/watch?v=Rjd1ZqJ89N4 but first connect to hpsetup and then print the first network config page
Then should see it in Add printer -> Default (on OS X 10.6)
Thunderbird: specify different “Trash” folder
Linux: Edit → Preferences → Advanced – General tab → Config Editor. Get the server number # from inspecting different mail.server.server#.name values. Right click somewhere in the box, select New → String, name is mail.server.server#.trash_folder_name (with the correct value for #), value is the name of the desired trash folder (e.g. “Deleted Messages”). Restart Thunderbird.
Slow Safari
Disable DNS prefetching: defaults write com.apple.safari WebKitDNSPrefetchingEnabled -boolean false
Re-enable: defaults delete com.apple.safari WebKitDNSPrefetchingEnabled
Rebuild the LaunchServices database (clean up “Open with” drop-down menu)
sudo /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -kill -r -domain system -domain local -domain user
UCB 7th floor printers
hp2=128.138.191.39, hp3=128.138.191.40, copier=128.138.191.45
Compiling on lstcluster
lstcluster.univ-lyon1.fr, 134.214.125.165, access through lstblende, lstblende.univ-lyon1.fr, 134.214.125.167
ifort -lscs -O3 -r8 -o 2phase 2phase.f90
lstblende – RAM 15.9 GB, 64 arch