Once you have connected to mongod in your environment through mongo shell. You want to know about the databases or may be all collection in a particular database. You can use number of options while connecting to mongo but I prefer it in a simple way
mongo –host yourhost –port 27017 -u username -p password
*mongo commands and scripting language is case sensitive ~Be Carefull *
On successful login, you will be presented with mongo CLI. Here are the 5 commands you must know
1): show
Use show command to get or print information about databases, collections, users, roles and profile
- show dbs — show list of database in mongo instance you connected to
- show dbs — show list of collection in current database you are in
- show users — show list of user for current database
- show roles —show list of user defined or system roles in current database
- show profiles –show the five most recent operations that took 1ms or more
2) : db.serverBuildInfo()
It is very useful command (pretty much like @@Version in SQL Server world) which return a document that will let you understand about mongo version, build, edition and storage engines.
3) : db.currentOp()
Returns a document about in-progress sessions for the database instance. You can see each session’s info like seconds running, query, lock etc. Here what I use very frequently,
db.currentOp(
{
“secs_running” : { “$gt” : 3},
“active” : true
}
)
4) : db.killOp
Terminates an operation as specified by the operation ID. Use db.currentOp() to find current operations and their corresponding IDs
5) : db.collectionname.find()
It is like querying a table in SQL world with SELECT. It will show the list documents in a collection.
adrshen 