BASH cheat sheet

This is my cheat sheet BASH. I'm here to collect useful code snippets and constructs that I had to google from time to time or otherwise man'en. The article serves me personally as a reference book but could be useful to others who often have the Bourne-again shell to do.

Grind

  while [1] # Endless loop
 do
     echo "Blah"
 done 

  for i in $ (ls / etc)
 do
   echo $ i
 done

 for i in `seq 1 10`;
 do
   echo $ i
 done 

Case

  case "$ 1" in
      a)
             echo "a"
             ;;
      b)
             echo b "

             ;;
      *)
              echo "$ 1 is not a or b"
              ;;
 esac 

  Switches for Test: http://bash-hackers.org/wiki/doku.php/commands/classictest

 or

 / Usr / bin / [- help 

If-Then-Else

  if ["$ 1" = "a"] then
    echo "a"
 else
     echo "not a"
 fi 

dpkg + apt

  # List files installed from a package
 dpkg-L [package name]

 # List files IN a package
 dpkg-c [package.deb]

 # Info about a package
 dpkg-I [package.deb]

 # List all installed packages
 dpkg-l
 dpkg - get-selections> getselections.txt

 Installation # import from file selection
 dpkg - set-selections <getselections.txt 

netstat

  # Lists all open ports to the outside
 netstat-lpn | grep LISTEN | grep-v localhost 

mdadm

  # Test your email
 # Uses MAILADDR from / etc / mdadm / mdadm.conf
 mdadm - monitor -1 / dev/md0-t

 # Device to add to the array
 mdadm - add / dev/md0 / dev/sda1

 # Remove device from the array
 mdadm - remove / dev/md0 / dev/sda1

 # Remove Faulty Devices
 mdadm - manage / dev/md0 - remove faulty
 mdadm - manage / dev/md0 - remove failed

 # Re-install boot loader
 grub
 grub> root (hd0, 0)
 grub> setup (hd0)

 # Disk information output
 smartctl-i / dev / sdx 

ext

  # Disklabel set
 e2label device label 

Screen

  # Screens to automatically generate scripts and task start screen
 screen-S [screen name]-d-m [script.sh]

 # Create a new screen or to change existing
 screen-R-d [screen name]

 # Keystroke to exit a screen
 CTRL - A - D 

mysql

 # All databases into a dump file mysqldump-u root-psecret - all-databases> backup.sql # Only the database structure into a dump file mysqldump-u root-psecret - no-data - all-databases> backup.sql # Dump Restore mysql-u root-psecret <backup.sql # root password reset / etc / init.d / mysql stop echo "SET PASSWORD FOR 'root' @ 'localhost' = PASSWORD ('new password')"> ~ / setrootpassword.sql mysqld_safe - init-file = ~ / setrootpassword.sql # [ctrl] + [c] / etc / init.d / mysql start rm-f ~ / setrootpassword.sql 

imagemagick

  # Resize all images in current directory
 mogrify-resize 800x600. / *. JPG

 # All images in the current directory to PNG convert
 mogrify-format png. / * 

unionfs-fuse

  # Union between a and b in c
 # Will be posted on a

 unionfs-fuse-o cow / home / a RW = :/ home / b = RW / home / ww / Desktop / c 

ffmpeg

  # Convert flv to 3gp
 ffmpeg-i-f 3gp-vcodec in.flv h263-s 176x144-ab 12.2k-ar 8000-ac 1 out.3gp

 # Convert from just about any format to any other as loss free as possible
 ffmpeg-i infile.ext-pass 2-sameq outfile.ext 

find

  # Find files, and do something with them
 find.  -Name "* mp3."-Exec file {} \;

 # Soft links can view and
 find.  -Type l-exec ls-l {} \; 

 # Include all files in a directory
 find / directory-type f | wc-l 

sudo

  # / Etc / sudoers
 # User username password command without a permit execute a privileged
 # (Appended at the very end must be from / etc / sudoers)

 username ALL = NOPASSWD: / sbin / reboot 

iptables

  # Allow everything on INPUT
  iptables-F; iptables-P INPUT ACCEPT

 # Debug connections
 # Packet counters in a chain to 0
 iptables-Z INPUT

 # Chain with counter display package
 iptables-L INPUT-v 

FTP mount

  mkdir / tmp / mnt
 modprobe fuse
 curlftpfs-v-o nonempty ftp.host.com-o user = username: password / tmp / mnt
 umount / tmp / mnt 

umount "device is busy" - find-blocking process

  fuser-m [mountpoint] 

wget mirrorn website

  wget-km http://www.website.com 

SAMBA mount

  mount.cifs / / 192.168.0.1/share / media / share-o username = $ USERNAME, password = $ PASSWORD 

32bit or 64bit

  getconf LONG_BIT 

/ Etc / fstab

  NFS:
 192.168.0.1 :/ home / home nfs rsize = 8192 wsize = 8192, hard, intr 0 0 

Disk Full - Find memory hogs

  apt-get install ncdu
 ncdu

 # / Mounts without any other FS / mnt
 # (If data cover mounts on the local disk)
 mnt / bind / - mount, du-sm / mnt 

Full encryption of the system

  Very good tutorial by Andreas Haerter:

 http://blog.andreas-haerter.com/2011/06/18/ubuntu-festplattenvollverschluesselung-lvm-luks 

Disk via the LAN cloning

  dd if = / dev / hda | ssh-c blowfish-C root@otherbox.ip.addr dd of = / dev / hda 

Current UNIX TIMESTAMP output (ET)

  date +% s 

Asterisk

 # Convert sound file in Asterisk playable format
 ffmpeg-i-ar 8000-ac ./input.mp3 1 from 64. / output.wav