/ mozey.co / blog

linux log files

April 18, 2016

🔗 Linux Log Files

🔗 System Logs

🔗 Authorization Log

Info about user logins and usage of the sudo command

grep sshd /var/log/auth.log | tail -n 50

grep sudo /var/log/auth.log | tail -n 50

Filter by month, day and hour

grep "Apr 18 13" /var/log/auth.log

🔗 Daemon Log

Info about running system and application daemons

tail /var/log/daemon.log 

🔗 Debug Log

Detailed debug messages from the Ubuntu system and applications

tail /var/log/debug

🔗 Kernel Log

Detailed log of messages from the Ubuntu Linux kernel

tail /var/log/kern.log

🔗 Kernel Ring Buffer

Not really a log file per se, but rather an area in the running kernel you can query for kernel bootup messages via the dmesg utility

dmesg | tail

dmesg | grep pnp | tail

/var/log/dmesg | tail

🔗 System Log

Most information about Ubuntu system, also contains everything that used to be in /var/log/messages

tail /var/log/syslog

🔗 Application Logs

🔗 Apache HTTP Server Logs

tail /var/log/apache2/access.log

tail /var/log/apache2/error.log

🔗 System Logging Daemon (syslogd)

Awaits logging messages from numerous sources and routes the messages to the appropriate file or network destination

Configuration file is

/etc/syslog.conf

Place message into the System Log

logger This is the message text
 
tail /var/log/syslog

See link above for more options