Build GeoJSON shapes for all US cities.

build.sh

#!/bin/bash

# Extract the US zip-code shapes and convert to a single US-wide
# GeoJSON file
echo -n "Extracting US-wide GeoJSON file (takes ~10 mins)..."
mkdir tl_2014_us_zcta510
unzip -qq tl_2014_us_zcta510.zip -d tl_2014_us_zcta510
ogr2ogr -f GeoJSON -t_srs crs:84 tl_2014_us_zcta510.geojson tl_2014_us_zcta510/tl_2014_us_zcta510.shp
rm -r tl_2014_us_zcta510
echo "done."

# Join the {zip->city} mapping to create per-city files with the
# GeoJSON sub-documents for each zip-code in the city.
echo -n "Creating per-city partial GeoJSON files (takes ~15 mins)..."
mkdir per_city_partials
join -1 2 -2 1 <(sort -k 2,2 us_city_zips.tsv) <(cat tl_2014_us_zcta510.geojson | gawk '{ match( $0 , /ZCTA5CE10\": \"([0-9]+)\"/, arr ); if ( arr[1] != "" ) print arr[1], $0 }' | sort) | sed 's/,$//g' | gawk '{ city="per_city_partials/" $2; $1=$2=""; print $0 >> city; close(city) }'
echo "done"

# For each city, combine the zip-code GeoJSON sub-documents into a
# single city-level GeoJSON document.  Also annotate the resulting
# GeoJSON document with properties for the city ID and city name.
echo "Combining partial GeoJSON files into complete per-city GeoJSON files with annotations (takes ~2 hours)..."
mkdir per_city_geojson
for i in per_city_partials/*
do
    id="${i#*/}"
    state="${id%%_*}"
    city="${id#*_}"
    city="${city//_/ }"
    cat <( echo '{ "type":"FeatureCollection", "features":[' ; gawk '{ if ( NR > 1 ) print "," ; print $0 }' ${i} ; echo "]}" ) | mapshaper - -dissolve2 -simplify 10% -each "\$.properties = { id: \"${id}\", state: \"${state}\", city: \"${city}\" }" -o per_city_geojson/${id}.json
done
echo "Done generating complete per-city GeoJSON files."

# Catenate the per-city GeoJSON files into a single US-wide GeoJSON
# file.
echo -n "Combine per-city GeoJSON files into single US-wide GeoJSON file..."
echo '{"type":"FeatureCollection","features":[' > us_cities.geojson
for i in per_city_geojson/*
do
    cat ${i}
    echo
done | sed 's/^[{]"type"[:]"FeatureCollection"[,]"features"[:][[]//' | sed 's/\]\}$//' | awk '{ if ( NR > 1 ) printf( "%s", ", ") ; print $0 }' >> us_cities.geojson
echo ']}' >> us_cities.geojson
echo "done."

# Last, but not least, convert GeoJSON into a Shapefile .zip
echo "Convert US-wide GeoJSON file to shapefile .zip..."
mkdir shapefile
cd shapefile
ogr2ogr -F "ESRI Shapefile" us_cities.shp ../us_cities.geojson OGRGeoJSON
zip -qq ../us_cities.zip us_cities.dbf us_cities.prj us_cities.shp us_cities.shx
cd ..
rm -rf shapefile
echo "done."

echo ; echo "All done!"

Have you actually done this? Do you have geojson data for all us cities?