Handy Locations

Password File

/etc/passwd

Log Files

/var/log/

Installing Stuff

/usr/src is where you do work such as installing packages

Plesk Backups

/var/lib/psa/dumps/1/

Plesk Logs

/usr/local/psa/admin/logs

find all files over a certain size

cd /
find / -type f -size +10000k -exec ls -lh {} \; | awk '{ print $5 ": " $9 }' |sort -n | mail -s "files over 10000k" cschwieterman@xxxxxxxxxxxxx.com

cd /
find / -type f -size +50000k -exec ls -lh {} \; | awk '{ print $5 ": " $9 }' |sort -n


Change the 10000k or 50000k to the size you need.

Custom Commands

Here is a list of custom commands I usually create on linux based systems.

htr is a custom command that will restart apache
echo "service httpd restart" > /usr/bin/htr ; chmod 700 /usr/bin/htr

awstats is a custom command that will update ALL STATS for all sites that have a config file
echo "/usr/local/awstats/tools/awstats_updateall.pl now" > /usr/bin/awstats ; chmod 700 /usr/bin/awstats

mail-ps is a custom command to mail the current process list to statusupdate@xxxxxxx.net
echo "ps auxw | mail -s \"Server: Current Processes\" statusupdate@xxxxxxx.net" > /usr/bin/mail-ps ; chmod 700 /usr/bin/mail-ps

mail-netstat is a custom command to mail the current open port list to statusupdate@xxxxxxx.net
echo "netstat -nape | mail -s \"Server: Current Active Internet Connections\" statusupdate@xxxxxxx.net" > /usr/bin/mail-netstat ; chmod 700 /usr/bin/mail-netstat

Change Permissions of files (chmod)

Here's another from my scrap notes.

chmod 000 filename.abc

(defaults are usually 755 for folders, 644 for files)

Numbers correspond to users. 1st=Owner; 2nd=Group; 3rd=Other
(-rwxrwxwrx = 777, -rwxr-xr-x = 755, -rw-r--r-- = 644, etc.)
7 = Read + Write + Execute
6 = Read + Write
5 = Read + Execute
4 = Read
3 = Write + Execute
2 = Write
1 = Execute
0 = All access denied

qmail

Flush the queue and send all mail

killall -ALRM qmail-send

I use this every now and then on my failover mail queue.

Common MySQL Commands

From root command prompt

Mysql Prompt: mysql -uadmin -p`cat /etc/psa/.psa.shadow`

Cool commands:
show variables like 'have_query_cache';
show variables like 'query%';
SHOW STATUS LIKE 'Qcache%';


FLUSH QUERY CACHE - defrag
RESET QUERY CACHE - empty


MySQL Start
/etc/init.d/mysqld start

To update mysql root password:

mysql
mysql> USE mysql;
mysql> UPDATE user SET Password=PASSWORD('new-password') WHERE user='root';
mysql> FLUSH PRIVILEGES;

Common Linux Commands I Use

Processes

To view current processes running on the system use the following commands:

ps auxw # USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
ps auxw | grep | sort –n

Netstat

To view open connections and ports use netstat.

Netstat –nape

Outputting to Null

> /dev/null

TAR

To tar a file:

tar -cf nameOfTar.tar Folder1 Folder2

To untar a file

tar -xvf nameOfTar.tar

To untar a gzip file

tar -zxvf nameOfTar.tar.gz

Touch

A simple command that can create a file quickly

touch /var/log/somelogname.log
chmod 700 /var/log/somelogname.log
echo “this is a log file” > /var/log/somelogname.log
cat /var/log/somelogname.log


HTTPD Restart

/etc/init.d/httpd restart


Server Version

cat /etc/redhat*

CentOS release 4.5 (Final)


2)On SUSE Linux,
$cat /etc/SuSE-release


Top

Top displays a lot of system information in real time. CPU/memory/etc. It is a resource hog though.

top

Free Memory

free –m // memory


FTP

ftp server.com

use ftp -i server.com to remove confirmations. For example, downloading multiple files requires the use of mget *.*. Without logging in with -i it will force you to acknowledge the download of each file.

Reboot

shutdown -r now is reboot

Nice

Usage: nice [OPTION] [COMMAND [ARG]...]
Run COMMAND with an adjusted scheduling priority.
With no COMMAND, print the current scheduling priority. ADJUST is 10
by default. Range goes from -20 (highest priority) to 19 (lowest).

-n, --adjustment=ADJUST increment priority by ADJUST first
--help display this help and exit
--version output version information and exit

Example:
cd /; nice -n 15 /usr/bin/clamscan -r | mail -s "Server: AV Scan Results" chad@xxxxxxxxxxxx.com


Display resources

cat /proc/user_beancounters

egrep "failcnt|numiptent" /proc/user_beancounters

httpd configtest

/etc/init.d/httpd configtest