fduran

#!/bin/bash
# generate a number of files with random sizes in a range
 
min=1      # min size (MB)
max=10     # max size (MB)
nofiles=20 # number of files
 
for i in `eval echo {1..$nofiles}`
do
    dd bs=1M count=$(($RANDOM%max + $min)) if=/dev/urandom of=./files/file$i

fduran

# www.fduran.com
# exclude a process from being killed by oom killer
echo -17 > /proc/$PID/oom_adj

# The possible values of oom_adj range from -17 to +15. The higher the score, more likely the associated process is to be killed by OOM-killer: https://lwn.net/Articles/317814/

fduran

# www.fduran.com
# what is this process? - mini forensics on unknown running process

ls -l /proc/$pid/exe
dpkg -S /path/to/process_binary
strings /path/to/process_binary
hexdump -C /path/to/process_binary
netstat -tapn|grep tang
lsof $pid

fduran

# www.fduran.com
# set up Celery with Django (dev queuing)

(source activate)

# install (kombu is included)
pip install celery
pip install django-celery

fduran

# Postfix mail review
# look at logs
tail /var/log/mail.log
tail /var/log/mail.err
 
# view queue
mailq
 
# delete deferred messages in queue
postsuper -d ALL deferred

fduran

# www.fduran.com
# Run script detached from an SSH terminal
nohup script.sh </dev/null &

fduran

# www.fduran.com
# check ssl connection

echo '' |openssl s_client -ssl3 -connect google.com:443 -CApath /usr/share/ssl-cert

fduran

# www.fduran.com
# sync (copy) local to remote server directory
# take out dry-run after test
 
rsync --dry-run -azvrh -e 'ssh -p 2022' --exclude 'donotcopy' /var/www/ user@10.0.0.1:/var/www/
 
# options:
a: archive, preserve metadata
z: compression
v: verbose

fduran

# www.fduran.com
# test cronjobs

# cron running?
pgrep cron
service cron status
# or crond for redhat, other distros above

# add line in crontab:
*/1 *   * * *   root   /bin/date >> /tmp/cronlog

fduran

# www.fduran.com
# renice many processes with the same name
for i in `pgrep processname`; do renice 20 -p $i; done