5.5 and 5.6 install problem, server says fails to start

i tried doing a clean install of 5.5 and 5.6, but when starting the server i get a failed to start error, ONLY when using a custom my.cnf from the toolkit, the server will start without the my.cnf in place. when using the custom my.cnf, there error is:

* Starting MySQL (Percona Server) database server mysqld [fail]

yet the server did start, however i must use the kill command to kill it

my custom my.cnf is below, i narrowed down the problem, if i comment out:

[mysqld]
socket = /var/lib/mysql/mysql.sock

then it starts and shuts down fine, without errors

the my.cnf i have is:

[mysql]

# CLIENT #
port = 3306
socket = /var/lib/mysql/mysql.sock

[mysqld]

# GENERAL #
user = mysql
default-storage-engine = InnoDB
socket = /var/lib/mysql/mysql.sock
pid-file = /var/lib/mysql/mysql.pid

# MyISAM #
key-buffer-size = 32M
myisam-recover = FORCE,BACKUP

# SAFETY #
max-allowed-packet = 16M
max-connect-errors = 1000000
skip-name-resolve
sql-mode = STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_AUTO_VALUE_ON_ZERO,NO_ENGINE_SUBSTITUTION,NO_ZERO_DATE,NO_ZERO_IN_DATE,ONLY_FULL_GROUP_BY
sysdate-is-now = 1
innodb = FORCE
innodb-strict-mode = 1

# DATA STORAGE #
datadir = /var/lib/mysql/

# BINARY LOGGING #
log-bin = /var/lib/mysql/mysql-bin
expire-logs-days = 14
sync-binlog = 1

# CACHES AND LIMITS #
tmp-table-size = 32M
max-heap-table-size = 32M
query-cache-type = 0
query-cache-size = 0
max-connections = 500
thread-cache-size = 50
open-files-limit = 65535
table-definition-cache = 1024
table-open-cache = 2048

# INNODB #
innodb-flush-method = O_DIRECT
innodb-log-files-in-group = 2
innodb-log-file-size = 256M
innodb-flush-log-at-trx-commit = 2
innodb-file-per-table = 1
innodb-buffer-pool-size = 4G

# LOGGING #
log-error = /var/lib/mysql/mysql-error.log
log-queries-not-using-indexes = 1
slow-query-log = 1
slow-query-log-file = /var/lib/mysql/mysql-slow.log

there is no useful reason given in the error log file, during both cases, with and without the startup fail error, the log looks as follows:

140418 06:08:32 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql/
140418 6:08:32 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated and will be removed in a future release. Please use the full name instead.
140418 6:08:32 [Note] Plugin 'FEDERATED' is disabled.
140418 6:08:32 InnoDB: The InnoDB memory heap is disabled
140418 6:08:32 InnoDB: Mutexes and rw_locks use GCC atomic builtins
140418 6:08:32 InnoDB: Compressed tables use zlib 1.2.7
140418 6:08:32 InnoDB: Using Linux native AIO
140418 6:08:32 InnoDB: Initializing buffer pool, size = 4.0G
140418 6:08:32 InnoDB: Completed initialization of buffer pool
140418 6:08:32 InnoDB: highest supported file format is Barracuda.
140418 6:08:32 InnoDB: Waiting for the background threads to start
140418 6:08:33 Percona XtraDB (http://www.percona.com) 5.5.36-34.2-34.2 started; log sequence number 1597945
140418 6:08:33 [Note] Event Scheduler: Loaded 0 events
140418 6:08:33 [Note] /usr/sbin/mysqld: ready for connections.
Version: '5.5.36-34.2-648.quantal-log' socket: '/var/run/mysqld/mysql.sock' port: 3306 (Ubuntu)

ok, i figured it out, i had to change my.cnf from

socket = /var/lib/mysql/mysql.sock

to

socket = /var/run/mysqld/mysqld.sock

in both places