IV Notes

Command line

  • rsync is a better cp. You can easily get a copy with progress bar by just using rsync -P file_a file_b It also has a ton of other useful functions. Originally picked it up from this post: https://solovyov.net/blog/2011/rsync-better-cp/
  • To get the full processor name on Mac:
➜ sysctl -n machdep.cpu.brand_string
Intel(R) Core(TM) i7-3740QM CPU @ 2.70GHz
  • To create a zero-filled file of specified size:
dd if=/dev/zero of=32mb.bin bs=32m count=1
  • To run a program and report its maximum memory usage and other interesting things we can use usual GNU time(on Mac: brew install gnu-time will install it as gtime).
➜ gtime -v target/release/c
iterator returned: 384
Command being timed: "target/release/c"
User time (seconds): 0.77
System time (seconds): 0.62
Percent of CPU this job got: 99%
Elapsed (wall clock) time (h:mm:ss or m:ss): 0:01.40
Average shared text size (kbytes): 0
Average unshared data size (kbytes): 0
Average stack size (kbytes): 0
Average total size (kbytes): 0
Maximum resident set size (kbytes): 3125868
Average resident set size (kbytes): 0
Major (requiring I/O) page faults: 0
Minor (reclaiming a frame) page faults: 781620
Voluntary context switches: 3
Involuntary context switches: 112
Swaps: 0
File system inputs: 0
File system outputs: 0
Socket messages sent: 0
Socket messages received: 0
Signals delivered: 0
Page size (bytes): 4096
Exit status: 0
  • Or even simpler, to just print maximum resident set size at the end: gtime -f %M program_name
  • Convert an SVG files to multiple PNG files with different resolutions and pack them all in an ICO file:
# install `svgexport` and `imagemagick`:
brew install imagemagick
npm install -g svgexport
# this worked better than ImageMagick for me:
svgexport favicon.svg 16.png 16:16
svgexport favicon.svg 32.png 32:32
# and so on, and then combine them:
convert 16.png 24.png 32.png -colors 256 favicon.ico
  • Run a command every 5 seconds: watch -n5 command
  • Convert GPS routes from .gpx to .kml without creating lots of points:
    gpsbabel -i gpx -f input.gpx -o kml,points=0 -F output.kml