Below are some AT commands for ESP8266 and their outputs

AT
OK

AT+GMR
This will display firmware version and some other details 

AT+CIPMUX=1 
OK

AT+CWMODE=3 
OK

AT+CWJAP="WIRELESS-ROUTER","password"
[WIFI DISCONNECTED] (if it is already connected)
WIFI CONNECTED
WIFI GOT IP
OK

AT+CIPSTART=4,"TCP","x.x.x.x",80
4,CONNECT
OK

AT+CIPSEND=4,205
OK
> [at this point HTTP request will be made, read below for details]
Recv 205 bytes
SEND OK
+IPD,4,203:HTTP/1.1 200 OK
Date: Sun, 14 Feb 2016 20:33:16 GMT
Server: Apache/2.4.7 (Ubuntu)
X-Powered-By: PHP/5.5.9-1ubuntu4.14
Content-Length: 15
Connection: close
Content-Type: text/html

led_1=0|led_2=14,CLOSED

[The blue colored text above is what the server has sent in reply to the HTTP request]

AT+UART_CUR=2400,8,1,0,0
OK

[This command work with AT ver 6.0 and SDK ver 1.5.2. The changes will be temporary and will be restored to default on resetting. Use ]

AT+UART_DEF=2400,8,1,0,0

[This will make the change permanent. In case things gets wrong then reflash]

If AT+UART doesn't work then use 
AT+IPR

An extensive guide can be found here
https://github.com/espressif/ESP8266_AT/wiki/CWSAP

https://docs.espressif.com/projects/esp-at/en/latest/AT_Command_Set/Basic_AT_Commands.html