/sbin/ifconfig = network info
/sbin/lspci | grep -i vga = graphics card info
strings /bin/ls | grep -i libc = finds all occurrences of libc in ls
strings /bin/ls = lists all ASCII text in ls
su -c ‘gedit /etc/yum.conf’ = opens yum.conf file in gedit
tail -3 ok = last 3 lines from a file named ok
tail -6 .bash_history = last 6 commands
tail -5 filename.txt = prints last 5 lines of the file to the screen
tail -n 5 filename.txt = prints last 5 lines of the file
tail -f /var/log/messages = updates size of text file as it gets bigger
tail -f /var/log/messages = displays system messages live
tail -f /var/log/maillog = displays mail server messages live
tail -f /var/log/httpd/access_log = displays web server messages live
tar cvf abc.tar abc.txt = tars a file with verbose
tar xvf abc.tar = untars a file with verbose
tar c abc.txt | gzip -c > abc.tar.gz = archives file and zips a file (two steps)
tar czf abc.tar.gz abc.txt = archieves and zips a file (one step, z = unzip, c = create)
tar czvf abc.tar.gz abc.txt = archieves and zips a file with verbose
tar cjvf abc.tar.bz2 abc.txt = archieves and zips a file with bzip2
tar xzvf abc.tar.gz = unzips and untars file (one step, x = untar)
tar xjvf abc.tar.bz2 = unzips and untars file (one step, j = bzip2)
time = prints current time
time yum/command name = command’s excution time
top = lists process with cpu usage
top -d 5 = changes update delay to 5 seconds (from default 3)
top -u james = process info for user james
top -p 190,2690 = process for for id 190 and 2690
top -n 10 = refreshs the screen 10 times before quitting
top -b = runs in non-interative non-screen-oriented mode
touch name.txt = creates a file named name.txt
touch /var/log/btmp = enables recording of bad attempts
tree -dx = directory structure of the os
type php = path of executables/shell commands