Command line Fu

One way to check whether a library is installed is to use ld, e.g. check that zlib is installed: ld -lzlib If library is installed you’ll get something like this: ld: warning: -arch not specified ld: could not find entry point “start” (perhaps missing crt1.o) for inferred architecture x86_64 If library is not installed you’ll […]

The trick is to use vmstat and look at the number for “wait on acknowledge”. vmstat -S m 1 100 Look under “cpu” and the “wa” column. If this number is high, it is bad. It should be zero. Some sample output from vmstat looks like this: procs ———–memory———- —swap– —–io—- -system– —-cpu—- r b

Warning: This is not the hardest way to create a word cloud from pdf-documents, but it’s up there. Say you have directory containing pdf documents: $ ls a.pdf b.pdf c.pdf …

SYSTEM_PROFILER Show a very long list of details about your machine and kernel (verbose output) system_profiler

Found this nice post on good commands to know appart from the obvious top Basically they are top and vm_stat 5

I have a text file containing article references. It looks like this – Miller HJ (2004) Tobler’s First Law and spatial analysis. Ann Assoc Am Geogr 94:284–289. – Onsrud H, ed (2007) Research and Theory in Advanced Spatial Data Infrastructure Concepts (ESRI Press, Redlands, CA). – Egenhofer M (2002) Toward the geospatial semantic web. Advances

The following assumes a linux command line to be present (or Mac OS X terminal in my case). I want to wrangle text from the internet, turn it into JSON data, and ultimately stick it in CouchDB. Here I’m trying to turn a random text file containing prime numbers into structured JSON data that looks