Some basic linux commands...
FILE COMMANDS
ls - directory listing
ls -al - formatted listing with hidden files
cd dir - change directory to dir
cd - change to home
pwd - show current directory
mkdir dir - create directory dir
rm file - delete file
rm -r dir - delete directory dir
rm -f file - force remove file
rm -rf dir - remove directory dir
cp file1 file2 - copy file1 to file2
mv file1 file2 - rename file1 to file2
ln -s file link - create symbolic link 'link' to file
touch file - create or update file
cat > file - place standard input into file
more file - output the contents of the file
less file - output the contents of the file
head file - output first 10 lines of file
tail file - output last 10 lines of file
tail -f file - output contents of file as it grows
SSH
ssh user@host - connect to host as user
ssh -p port user@host - connect using port <PORT>
ssh -D port user@host - connect and use bind port
NETWORK
ping host - ping host "host"
whois domain - get whois for domain
dig domain - get DNS for domain
dig -x host - reverse lookup host
wget file - download file
wget -c file - continue stopped download
wget -r url - recursively download files from url
SYSTEM INFO
date - show current date/time
cal - show this month´s calendar
uptime - show uptime
w - display who is online
whoami - who are you logged in as
uname -a - show kernel config
cat /proc/cpuinfo - cpu info
cat /proc/meminfo - memory information
man command - show manual for command
df - show disk usage
du - show directory space usage
du -sh - human readable size in GB
free - show memory and swap usage
whereis app - show possible locations of app
which app - show which app will be run by default
SEARCHING
grep pattern files - search for pattern in files
grep -r pattern dir - search recursively for patterin in dir
command | grep pattern - search for pattern in the output of command
locate file - find all instances of file
PROCESS MANAGEMENT
ps - display currently active processes
ps aux - ps with a lot of detail
kill pid - kill process with pid "pid"
killall proc - kill all processes named proc
bg - lists stopped/background jobs, resume stopped job in the background
fg - bring most recent job to foreground
fg n - brings job n to foreground
FILE PERMISSIONS
chmod <octal> <file> - change permissions of file
4 - read (r)
2 - write (w)
1 - execute (x)
Order: owner / group / world
example given:
chmod 777 - rwx for everyone
chomd 755 - rwx for owner, rx for group/world
COMPRESSION
tar cf file.tar files - tar files into file.tar
tar xf file.tar - untar into current directory
tar tf file.tar - show contents of archive
tar flags:
c - create archive
t - table of contents
x- extract
f - specifies filename
z - us zip/gzip
j - bzip2 compression
k - do not overwrite
T - files from file
w - ask for confimation
v - verbose
gzip file - compress file and rename to file.gz
gzip - file.gz - decompress file.gz
SHORTCUTS
ctrl + c - halts current command
ctrl + z - stops current command
fg - resume stopped command in foreground
bg - resume stopped command in background
ctrl + d - log out of current session
ctrl + w - erases one word in current line
ctrl + u - erases whole line
ctrl + r - reverse lookup of previous commands
!! - repeat last command
exit - log out of current session