Useful unix commands

useful_unix_commands

#To check which programs are running on which ports
sudo lsof -i :80 # checks port 80

          COMMAND   PID          USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
          haproxy 32850          root    4u  IPv4 0xf27d639a63f41339      0t0  TCP *:http (LISTEN)

#To watch changes to a given folder
#To install this command on mac check out this link: http://osxdaily.com/2010/08/22/install-watch-command-on-os-x
watch -d ls -l 

#Displays the file system disk space usage
df -k

uname -a
          Darwin adil.local 13.1.0 Darwin Kernel Version 13.1.0: Thu Jan 16 19:40:37 PST 2014; root:xnu-2422.90.20~2/RELEASE_X86_64 x86_64

#find filenames quickly          
locate crontab 

#changing the ulimit and starting mongo in the background
ulimit -n 2048 && sudo ./mongod --fork --logpath /var/log/mongodb.log