Cambiando formato de timestamp con awk

Una linea con epoch time, latitud y longitud.

El epoch time se esta reemplazando por la fecha en formato "%Y%m%dT%H%M%S"

echo "1288552753,38.995177,-76.881886" | \
TZ=UTC awk -F, '{ print strftime("%Y%m%dT%H%M%S",$1)","$2","$3 }'

A quick tutorial for sed.

http://www.grymoire.com/Unix/Sed.html

Usando indice de Qgis con Python

Si es que alguna vez tienen que asignar un lat long a una id de un polygono, una forma de hacerlo procesando por linea es usando la API de Qgis

from qgis.core import *

QgsApplication.setPrefixPath("/usr", True)
QgsApplication.initQgis()


vlayer = QgsVectorLayer( "polygons.shp", "temp_layer", "ogr" )
provider = vlayer.dataProvider()
#main dict to get precalculated values from layer
id2feat = {}
#spatial index to optimize lookup
index = QgsSpatialIndex()
#retrive just the first field from the map layer
provider.select([ 0 ])

#temporal feature
feat = QgsFeature()
while provider.nextFeature( feat ):
    index.insertFeature( feat )
    id2feat[ feat.id() ] = str( feat.attributeMap()[ 0 ].toString() )

for line in sys.stdin:
    fields = line.strip().split(',')
    #read longitude and latitude values
    if len( fields[ 0 ] ) and len( fields[ 1 ] ):
        longitude = float( fields[ 0 ] )
        latitude = float( fields[ 1 ] )
    else:
        print ','.join( fields + [ '' ] )
        continue
    #query geometries
    rect = QgsRectangle(longitude,latitude,longitude,latitude)
    point = QgsGeometry.fromPoint( QgsPoint( longitude, latitude ) )
    #query the index for bbox intersections
    intersects = index.intersects( rect )
    found = False

    for i in intersects:
        provider.featureAtId( i, feat )
        if point.intersects( feat.geometry() ):
            print ','.join( fields + [ id2feat[ i ] ] )
            ##IN CASE WE CARE ABOUT JUST ONE INTERSECTION
            found = True
            break
    if not found:
        print ','.join( fields + [ '' ] )

Cambiar de usuario en svn

Perdonen lo básico, pero siempre se me olvida...

Cómo cambiar de usuario en svn

svn --username=new_user

va a preguntar por el password del nuevo usuario, y en lo sucesivo quedará ese usuario almacenado para todas las futuras transacciones con svn.

Postgres Statistics

These are some queries that could be useful, extracted
from Zabbix project.

psql --version|head -n1
psql -t -c "select sum(numbackends) from pg_stat_database"
psql -t -c "select sum(xact_commit) from pg_stat_database"
psql -t -c "select sum(xact_rollback) from pg_stat_database"
psql -t -c "select sum(xact_commit) from pg_stat_database"
psql -t -c "select sum(xact_rollback) from pg_stat_database"
psql -t -c "select pg_database_size('$1')"
psql -t -c "select numbackends from pg_stat_database where datname = '$1'"
psql -t -c "select tup_returned from pg_stat_database where datname = '$1'"
psql -t -c "select tup_fetched from pg_stat_database where datname = '$1'"
psql -t -c "select tup_inserted from pg_stat_database where datname = '$1'"
psql -t -c "select tup_updated from pg_stat_database where datname = '$1'"
psql -t -c "select tup_deleted from pg_stat_database where datname = '$1'" 
psql -t -c "select tup_returned from pg_stat_database where datname = '$1'"
psql -t -c "select tup_fetched from pg_stat_database where datname = '$1'"
psql -t -c "select tup_inserted from pg_stat_database where datname = '$1'"
psql -t -c "select tup_updated from pg_stat_database where datname = '$1'"
psql -t -c "select tup_deleted from pg_stat_database where datname = '$1'"

And oid2name is very useful too, we can know what is the OID code for each
object in our database

 /usr/lib/postgresql/8.3/bin/oid2name  -d database -x

copy files to another machine using tar

tar cf - * | ssh user@host "(cd /destination_dir; tar xf -)"

Mostrando nulo cuadn NULL en postgres

\pset null nulo

PostgreSQL Tunning Link

http://www.postgresql.org/files/documentation/books/aw_pgsql/hw_performance/0.html

Creando un RAM Disk

mount -o size=5G -t tmpfs tmpfs /mnt/ramdb

Mas un validador de RUT en javascript

Buscando por la red encontré varios validadores de RUT, pero los encontré amorfos y con mucho código extra. Como soy niubi en esto, espero vuestros comentarios y recomendaciones.

// String aceptado debe incluir solo numeros y "k"
function rut_check(rut){
    var sum = 0;
    var tail = rut.slice(-1);

    for(f = 2, i = 0, j = rut.length - 2; i < rut.length - 1; ++i, --j, ++f){
        f = (f > 7) ? 2 : f;
        sum += f * rut.substr(j, 1);
    }

    digit = 11 - (sum % 11);
    digit = (digit == 11) ? 0 : digit;
    digit = (digit == 10) ? "k" : digit;

    return digit.toString() == tail;
}

Para terminar, condimente con este pedazo de código:

// Funcion para permitir solo entrada numerica o k
function rut_validkey(e){
    var key;

    if(window.event) e = window.event // Windows Support
    key = e.keyCode ? e.keyCode : e.which; // Firefox & Chromium support

    // control keys
    if(key==8 || key==9 || key==13 || key==27 || (key > 36 && key < 41))
        return true;

    if(key == 107 || key == 75 || (key > 47 && key < 58))
        return true;
    return false;
}