grep, swap, mongo

SWAP.txt

@@ -6,7 +6,7 @@ Linux SWAP recommended size
 ---------------------------
 
 .. note::
-    
+
     It's not a rule. It's only recommendation for general configurations.
 
 ===== ====
@@ -24,17 +24,19 @@ SWAP in file
 
     sudo dd if=/dev/zero of=/swapfile bs=1M count=4096
     sudo chmod 600 /swapfile
-    sudo mkswap /swapfile	
+    sudo mkswap /swapfile
 
 
-2. Disable all SWAP::
+2. Disable SWAP::
 
-    sudo swapoff -a		
+    sudo swapoff /swapfile
+    # or disable all swap
+    sudo swapoff -a
 
 
 3. Connect new SWAP file::
 
-    sudo swapon /swapfile	
+    sudo swapon /swapfile
 
 
 4. Add new SWAP to fstab (auto mount when system start)::
@@ -46,15 +48,15 @@ SWAP in file
 
     sudo sysctl -w vm.swappiness=30
 
-    
+
 
 Automated swapfile creation
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 ::
 
     #!/bin/bash
-    
+
     set -e
 
     # SWAP file size in MB
@@ -71,8 +73,8 @@ Automated swapfile creation
     sudo chmod 600 $SWAP_PATH
     sudo mkswap $SWAP_PATH
 
-    # Disable all SWAP
-    sudo swapoff -a
+    # Disable SWAP
+    sudo swapoff /swapfile
 
     # Connect new SWAP file
     sudo swapon $SWAP_PATH
@@ -82,5 +84,4 @@ Automated swapfile creation
 
     # Tweak system swap usage value
     sudo sysctl -w vm.swappiness=$VM_SWAPPINESS
-
-
+

linux_commands.txt

@@ -310,8 +310,8 @@ grep::
 
 
 Word replacement::
-
-    grep -iRl -E "(SOURCE)" | xargs sed -i "s/SOURCE/DEST/g"
+   
+    grep -Rl -E "(SOURCE)" ./* | xargs sed -i "s/SOURCE/DEST/g"
 
     sed -i "s@SOURCE@DEST@g" /path/to/file
 

mongodb.txt

@@ -0,0 +1,67 @@
+=======
+MongoDB
+=======
+
+
+Execute JS code::
+
+  mongo [db_name] --quiet --eval "<JS_code>"
+
+
+Print a list of all databases on the server::
+
+    show dbs
+    # or
+    db.getMongo().getDBNames()
+    # or
+    printjson(db.adminCommand('listDatabases'))
+
+
+Switch current database to <db>. The mongo shell variable db is set to the current database::
+
+    use <db>
+
+
+Backup/restore MongoDB data (docker)::
+
+    # dump
+    docker exec <container> sh -c 'mongodump --archive' > mongodb.dump
+
+    # restore
+    docker exec -i <container> sh -c 'mongorestore --archive' < mongodb.dump
+
+
+Print a list of all collections for current database::
+
+    show collections
+    # or
+    db.getCollectionNames()
+
+
+Print documents of collection::
+
+    db.<collection>.find().pretty()
+
+
+Get all documents of all collections of current DB::
+
+    var c = db.getCollectionNames();
+    for (var i = 0; i < c.length; i++) {
+       print('[' + c[i] + ']');
+       db.getCollection(c[i]).find().forEach(printjson);
+    }
+
+
+Get DBs, collections and docs count::
+
+    db.getMongo().getDBNames().forEach((d) => {
+      print('[' + d + ']');
+      db = db.getSiblingDB(d);
+      db.getCollectionNames().forEach((c) => {
+        print('\t' + c + ': ' + db.getCollection(c).count());
+      });
+    });
+
+    # single line
+    db.getMongo().getDBNames().forEach((d)=>{print('['+d+']');db=db.getSiblingDB(d);db.getCollectionNames().forEach((c)=>{print('\t'+c+': '+db.getCollection(c).count())})})
+