root@dev:~# mongo
 MongoDB shell version: ..
 connecting to: test
 > help
     db.help()          help on db methods
     db.mycoll.help()       help on collection methods
     rs.help()          help on replica set methods
     help connect         connecting to a db help
     help admin          administrative help
     help misc          misc things to know
     help mr           mapreduce help
     show dbs           show database names
     show collections       show collections in current database
     show users          show users in current database
     show profile         show most recent system.profile entries with time >= ms
     use <db_name>        set current database
     db.foo.find()        list objects in collection foo
     db.foo.find( { a : } )   list objects in foo where a == 
     it              result of the last line evaluated; use to further iterate
     DBQuery.shellBatchSize = x  set default number of items to display on shell
     exit             quit the mongo shell 

 db.help()
 DB methods:
     db.addUser(username, password[, readOnly=false])
     db.auth(username, password)
     db.cloneDatabase(fromhost)
     db.commandHelp(name) returns the help for the command
     db.copyDatabase(fromdb, todb, fromhost)
     db.createCollection(name, { size : ..., capped : ..., max : ... } )
     db.currentOp() displays the current operation in the db
     db.dropDatabase()
     db.eval(func, args) run code server-side
     db.getCollection(cname) same as db['cname'] or db.cname
     db.getCollectionNames()
     db.getLastError() - just returns the err msg string
     db.getLastErrorObj() - return full status object
     db.getMongo() get the server connection object
     db.getMongo().setSlaveOk() allow this connection to read from the nonmaster member of a replica pair
     db.getName()
     db.getPrevError()
     db.getProfilingLevel() - deprecated
     db.getProfilingStatus() - returns if profiling is on and slow threshold 
     db.getReplicationInfo()
     db.getSiblingDB(name) get the db at the same server as this one
     db.isMaster() check replica primary status
     db.killOp(opid) kills the current operation in the db
     db.listCommands() lists all the db commands
     db.printCollectionStats()
     db.printReplicationInfo()
     db.printSlaveReplicationInfo()
     db.printShardingStatus()
     db.removeUser(username)
     db.repairDatabase()
     db.resetError()
     db.runCommand(cmdObj) run a database command. if cmdObj is a string, turns it into { cmdObj : }
     db.serverStatus()
     db.setProfilingLevel(level,<slowms>) =off =slow =all
     db.shutdownServer()
     db.stats()
     db.version() current version of the server
     db.getMongo().setSlaveOk() allow queries on a replication slave server 

db.mycoll.help()
 DBCollection help
     db.mycoll.find().help() - show DBCursor help
     db.mycoll.count()
     db.mycoll.dataSize()
     db.mycoll.distinct( key ) - eg. db.mycoll.distinct( 'x' )
     db.mycoll.drop() drop the collection
     db.mycoll.dropIndex(name)
     db.mycoll.dropIndexes()
     db.mycoll.ensureIndex(keypattern[,options]) - options is an object with these possible fields: name, unique, dropDups
     db.mycoll.reIndex()
     db.mycoll.find([query],[fields]) - query is an optional query filter. fields is optional set of fields to return.
                            e.g. db.mycoll.find( {x:} , {name:, x:} )
     db.mycoll.find(...).count()
     db.mycoll.find(...).limit(n)
     db.mycoll.find(...).skip(n)
     db.mycoll.find(...).sort(...)
     db.mycoll.findOne([query])
     db.mycoll.findAndModify( { update : ... , remove : bool [, query: {}, sort: {}, 'new': false] } )
     db.mycoll.getDB() get DB object associated with collection
     db.mycoll.getIndexes()
     db.mycoll.group( { key : ..., initial: ..., reduce : ...[, cond: ...] } )
     db.mycoll.mapReduce( mapFunction , reduceFunction , <optional params> )
     db.mycoll.remove(query)
     db.mycoll.renameCollection( newName , <dropTarget> ) renames the collection.
     db.mycoll.runCommand( name , <options> ) runs a db command with the given name where the first param is the collection name
     db.mycoll.save(obj)
     db.mycoll.stats()
     db.mycoll.storageSize() - includes free space allocated to this collection
     db.mycoll.totalIndexSize() - size in bytes of all the indexes
     db.mycoll.totalSize() - storage allocated for all data and indexes
     db.mycoll.update(query, object[, upsert_bool, multi_bool])
     db.mycoll.validate() - SLOW
     db.mycoll.getShardVersion() - only for use with sharding 

{
     "host" : "dev",
     "version" : "..",
     "process" : "mongod",
     "uptime" : ,
     "uptimeEstimate" : ,
     "localTime" : ISODate("--T::.Z"),
     "globalLock" : {
         "totalTime" : ,
         "lockTime" : ,
         "ratio" : .,
         "currentQueue" : {
             "total" : ,
             "readers" : ,
             "writers" : 
         },
         "activeClients" : {
             "total" : ,
             "readers" : ,
             "writers" : 
         }
     },
     "mem" : {
         "bits" : ,
         "resident" : ,
         "virtual" : ,
         "supported" : true,
         "mapped" : 
     },
     "connections" : {
         "current" : ,
         "available" : 
     },
     "extra_info" : {
         "note" : "fields vary by platform",
         "heap_usage_bytes" : ,
         "page_faults" : 
     },
     "indexCounters" : {
         "btree" : {
             "accesses" : ,
             "hits" : ,
             "misses" : ,
             "resets" : ,
             "missRatio" : .
         }
     },
     "backgroundFlushing" : {
         "flushes" : ,
         "total_ms" : ,
         "average_ms" : .,
         "last_ms" : ,
         "last_finished" : ISODate("--T::.Z")
     },
     "cursors" : {
         "totalOpen" : ,
         "clientCursors_size" : ,
         "timedOut" : 
     },
     "network" : {
         "bytesIn" : ,
         "bytesOut" : ,
         "numRequests" : 
     },
     "opcounters" : {
         "insert" : ,
         "query" : ,
         "update" : ,
         "delete" : ,
         "getmore" : ,
         "command" : 
     },
     "asserts" : {
         "regular" : ,
         "warning" : ,
         "msg" : ,
         "user" : ,
         "rollovers" : 
     },
     "writeBacksQueued" : false,
     "ok" : 
 } 

use fragment
db.stats()

db.stats()
 {
         "db" : "fragment",
         "collections" : ,
         "objects" : ,
         "avgObjSize" : .,
         "dataSize" : ,
         "storageSize" : ,
         "numExtents" : ,
         "indexes" : ,
         "indexSize" : ,
         "fileSize" : ,
         "ok" : 
 } 

db.getCollectionNames()

db.getCollectionNames()
 [
     "u",
     "baseSe",
     "bytravel",
     "daodao",
     "goeu",
     "lotour",
     "lvping",
     "mafengwo",
     "sina",
     "sohu",
     "system.indexes"
 ] 

 show dbs
 admin  .GB
 local  (empty)
 pagedb .GB
 test  .GB
 use LuceneIndexDB
 switched to db LuceneIndexDB
 show dbs
 admin  .GB
 local  (empty)
 pagedb .GB
 test  .GB
 db
 LuceneIndexDB
 db.storeCollection.save({'version':'.', 'segment':'eol'})
 show dbs
 LuceneIndexDB  .GB
 admin  .GB
 local  (empty)
 pagedb .GB
 test  .GB

 <em>db.storeCollection.save({'version':'3.5', 'segment':'e3ol6'})</em> 

 db.storeCollection.remove({'version':'.'})
 db.storeCollection.findOne()
 null 

use pagedb
switched to db pagedb
db.page.ensureIndex({'title':, 'url':-})
db.system.indexes.find()
 { "name" : "_id_", "ns" : "pagedb.page", "key" : { "_id" : }, "v" : }
 { "name" : "_id_", "ns" : "pagedb.system.users", "key" : { "_id" : }, "v" : }
 { "_id" : ObjectId("efcfcaccd"), "ns" : "pagedb.page", "key" : {"title" : , "url" : - }, "name" : "title__url_-", "v" : }

 db.page.getIndexes()
 [
     {
         "name" : "_id_",
         "ns" : "pagedb.page",
         "key" : {
             "_id" : 
         },
         "v" : 
     },
     {
         "_id" : ObjectId("efcfcaccd"),
         "ns" : "pagedb.page",
         "key" : {
             "title" : ,
             "url" : -
         },
         "name" : "title__url_-",
         "v" : 
     }
 ]

db.mycoll.dropIndex(name)
  db.mycoll.dropIndexes() 

use fragment
db.baseSe.count()

 use fragment
 switched to db fragment
 db.baseSe.count()

 use fragment
db.baseSe.find().count()

use fragment
db.baseSe.storageSize()
142564096

db.baseSe.totalSize()
 144096000

mongod --dbpath /usr/mongo/data --logfile /var/mongo.log

mongod --auth --dbpath /usr/mongo/data --logfile /var/mongo.log 

mongod --repair

mongod -f /etc/mongodb.conf --repair

db.shutdownServer()

mongod --auth --dbpath /usr/mongo/data --logfile /var/mongo.log

db.addUser("admin", ",%F23_kj~00Opoo0+\/")

db.auth("admin", ",%F23_kj~00Opoo0+\/")

 {
     "user" : "admin",
     "readOnly" : false,
     "pwd" : "debfcbabbecd"
 } 

db.runCommand({fsync:1,lock:1})

db.currentOp()

 use admin
db.$cmd.sys.unlock.findOne()

db.currentOp()

mkdir testbak
cd testbak
mongodump

mongodump -d pagedb

mongodump -d pagedb -c page

cd testbak
mongorestore --drop

cd testbak
mongorestore -d pagedb --drop

cd testbak
mongorestore -d pagedb -c page --drop

mongoimport -d pagedb -c page --type csv --headerline --drop < csvORtsvFile.csv

mongoexport -d pagedb -c page -q {} -f _id,title,url,spiderName,pubDate --csv > pages.csv