Merge pull request #340 from Asta1986/postgres

added psql commands

cheat/cheatsheets/psql

@@ -0,0 +1,26 @@
+# psql is the PostgreSQL terminal interface. The following commands were tested on version 9.5.
+# Connection options:
+# -U username (if not specified current OS user is used).
+# -p port.
+# -h server hostname/address.
+
+# Connect to a specific database:
+psql -U postgres -h serverAddress -d dbName
+
+# Get databases on a server:
+psql -U postgres -h serverAddress --list
+
+# Execute sql query and save output to file:
+psql -U postgres -d dbName -c 'select * from tableName;' -o fileName
+
+# Execute query and get tabular html output:
+psql -U postgres -d dbName -H -c 'select * from tableName;'
+
+# Execute query and save resulting rows to csv file:
+psql -U postgres -d dbName -t -A -P fieldsep=',' -c 'select * from tableName;' -o fileName.csv
+
+# Read commands from file:
+psql -f fileName
+
+# Restore databases from file:
+psql -f fileName.backup postgres