diff --git a/bash.md b/bash.md
index 7c2f4c3..5f0bad2 100644
--- a/bash.md
+++ b/bash.md
@@ -35,4 +35,32 @@ wc - print line counts
 
 free - memory usage
 
-du - disk space by file
\ No newline at end of file
+du - disk space by file
+
+Resource Limit
+--------------------------------------------------------------------------------------------------------------
+`ulimit -a` to see all limits
+file at /etc/security/limits.conf to configure defaults
+
+
+MySQL
+---------------------------------------------------------------------------------------------------------------
+connection like `mysql -u root -p`
+
+`show databases;`
+
+user is in the format root@127.0.0.1
+
+`grant all prviileges on *.* to 'root'@'127.0.0.1'`
+
+data is stored in /var/lib/mysql
+
+failure to drop a db can be due to presence of unknown file in the database directory
+
+SSH
+----------------------------------------------------------------------------------------------------------------
+add client
+* client uses ssh-keygen to create a key in `/home/un/.ssh/` under files `id_rsa` and `id_rsa.pub`
+* host setup //etc/ssh/sshd_config to allow passwords and restart
+* client uses `ssh-copy-id host_address -p port_num` to move the key to the host
+* client uses `ssh` to login