I have been installed postgis following this guide. All is OK.

SELECT postgis_full_version();
"POSTGIS="2.1.7 r13414" GEOS="3.4.2-CAPI-1.8.2 r3921" PROJ="Rel. 4.8.0, 6 March 2012" GDAL="GDAL 1.10.1, released 2013/08/26" LIBXML="2.9.1" LIBJSON="UNKNOWN" TOPOLOGY RASTER"

But I have not the shp2pgsql in /usr/lib/postgresql/9.4/bin as you can see:

foo@bar:/usr/lib/postgresql/9.4/bin$ ls
clusterdb   initdb             pg_dump         pg_standby      psql
createdb    oid2name           pg_dumpall      pg_test_fsync   reindexdb
createlang  pg_archivecleanup  pg_isready      pg_test_timing  vacuumdb
createuser  pg_basebackup      pg_receivexlog  pg_upgrade      vacuumlo
dropdb      pgbench            pg_recvlogical  pg_xlogdump
droplang    pg_controldata     pg_resetxlog    postgres
dropuser    pg_ctl             pg_restore      postmaster

Why this happens? and how can I install it?