Linux Commands

1. RPM Version Info:

   • rpm -qa foo

2. Shutdown X11:

   • init 3

3. Reboot the System:

   • init 6

4. Mount a CDROM:

   • mount /dev/cdrom

5. Unmount a CDROM:

   • umount /dev/cdrom

6. List Start Up Scripts:

   • chkconfig --list

7. Turn On Start Up Script:

   • chkconfig service start

8. Turn Off Start Up Script:

   • chkconfig service off

9. Get the kernel version by typing

   • uname -r

10. Format USB Device to Vfat

    •  mkfs.vfat -F 32 /dev/sda1

11. How to create tarball's assuming your directory is called foo:</pre>

    • tar -cvzf foo.tar.gz /dir/foo

12. Add user to Virtual Postfix Database:</pre>

    • postmap virtual

13. Enable RAID1 Mirroring ndas:

    • ndasadmin enable -s 1 -o w 2

14. Reload Postfix:

    •  postfix reload

15. Produces Postfix Queue List:

    •  postqueue -p

16. Also Produces Postfix Queue List:

    • mailq

17. Flush Postfix Queues:

    •  postqueue -f

18. Remote Desktop for Windows (toggle -f on or off for fullscreen):

    • rdesktop -g 1152x768 -a 24 -b -f mail

19. Unzip bz2 files:

    • bzip2 -cd files.tar.bz2 | tar xvf -

20. Show program install path:

    • which {program}

21. Removes mail from mail queue

    • postsuper -d {queue id}>

22. Displays Hardware info from BIOS (must have installed dmidecode installed)

    • dmidecode

23. To get a Network list of current IP/Hostname's, type the following on the command line:

    • dig axfr hosthame

24. or to sort by IP type:

    • dig axfr hostname |grep IN | egrep A |sort -n  -k 5 -k 7 -t .

25. Type the following to setup rpmq to find true kernel version

    • alias rpmq='rpm --qf '\''%{NAME}-%{VERSION}-%{RELEASE}.%{ARCH}\n'\'' -q'

26. Type the following to determine the kernel version

    • rpmq kernel

27. List all PCI Devices:

    • lspci

28. Reload named:

    • rndc reload

29. Create Database:

    • create database {DATABASE NAME};

30. Create Database Privileges:

    • grant all privileges on {DATABASE NAME}.* to {DATABASE USER}@localhost identified by '{DATABASE PASSWORD}';

31. Set Privileges:

    • flush privileges;

32. Netstat IP,PORTS

    • netstat -tnap

33. Create QEMU Disk Images:

    • qemu-img create -f qcow {name}.img 3G

34. Install OS on QEMU Drive Image via CD-ROM

    • qemu -cdrom /dev/cdrom -hda {name}.img -m {memsize} -boot d

35. Install OS on QEMU Drive Image via IMAGE

    • qemu -cdrom {name}.iso -hda {name}.img -m {memsize} -boot d

36. Run QEMU Disk Images with Sound (Blaster16):

    • qemu -hda {name}.img -m {memsize} -soundhw es1370 -localtime

37. Move seamless between host and guest

    • qemu -hda {name}.img -m {memsize} -soundhw es1370 -localtime -usb -usbdevice tablet

38. Resize AVI Files (--export_asr 3 is widescreen and --export_asr 2 is fullscreen)

    • transcode -i INPUT.avi -y ffmpeg,ffmpeg -F mpeg4 -Z 320x,fast --export_asr 2 -o OUTPUT.avi -E 44100,16,2 -b 256

39. Start NetworkManager GUI Applet

    • nm-applet &

40. Set Password for MySQL Root

    • mysqladmin -u root password new-password

41. Remove User account and Home dir

    • userdel -r {username}

42. Mount an ISO image

    • mount -o loop -t iso9660 filename.iso /mnt/iso

43. Create random passwords

    • head /dev/urandom | strings

44. Show partions on a drive

    • sfdisk -l

45. You want to download all the GIFs from an HTTP directory. The command doesn't work since HTTP retrieval does not support globbing. In that case, use:

    • wget -r -l1 --no-parent -A.gif http://host/dir/

46. How to rsync

    • rsync -r -a -v -e "ssh -l {username}" --delete {remote machine}:/dir /dir

47. How to check memory

    •  ps -eo pid,ppid,rss,vsize,pcpu,pmem,cmd -ww --sort=pid

48. How to search and replace recursively within files

    •  find . -type f -exec sed -i s/search/replace/g {} +

49. How to convert Flac to MP3

    • for file in *.flac; do flac -cd "$file" | lame -h - "${file%.flac}.mp3"; done

50. How to check 3ware Hardware RAID status:

    •  tw_cli /c0 show

51. Dirvish Vault first init

    •  dirvish -vault ''vaultname'' --init

52. CIFS mount:

    • mount -o username=username,password=1234,uid=username,gid=groupname,iocharset=utf8,file_mode=0777,dir_mode=0777,noperm //host/disk /mnt/NAS/

53. How to install all development tools:

    • PRE Fedora 18: yum groups install "Development Tools"

    • POST Fedora 18: yum groupinstall development-libs development-tools gnome-software-development

    • apt-get install build-essential

54. How to enable ndadmin slot:

    • ndasadmin enable -s 1 -o w

55. How to install Debian Kernel headers:

    • apt-get install linux-headers-$(uname -r)

56. How to find the largest file/directory human readable from your current directory:

    • du -hsx * | sort -rh | head -10

57. How to list all installed PERL modules:

    • perl -MFile::Find=find -MFile::Spec::Functions -Tlwe  'find { wanted => sub { print canonpath $_ if /\.pm\z/ }, no_chdir => 1 }, @INC'

58. GLOBAL REPLACE in the files (change call to mall in all *.kumac files):

    • awk '{gsub("call", "mall", $0); print > FILENAME}' *.kumac

59. The fastest way to scan all your computers/network subnet for open ports ever:

    • nmap -T5 192.168.1.0/24

60. Convert virtual image files:

    • ovftool --lax input.ovf output.vmx

61. How to extract CPIO file:

    • cpio -id < filename

62. How to create a CPIO file:

    • find . | cpio --create --format='filename' > /tmp/newinitrd

63. How to all kernel mods:

    • find /lib/modules/*/ -type f -iname '*.ko' | less

64. Find binaries only in a directory:

    • find -type f -executable -exec sh -c 'test "$(head -c 2 "$1")" != "#!"' sh {} \; -print

65. Convert VMware to KVM:

    • qemu-img convert -O vmwareImage.vmdk kvmImage.qcow2

66. How to replace space with new line:

    • 'tr ' ' '\n' < fileName

67. How to reinstall GRUB2 Debian:

    • apt-get install --reinstall grub2-efi-amd64

68. How to change or modify SSH-Key pass phrase:

    • ssh-keygen -p -f keyfile

69. How find parition block size:

    • blockdev --getbsz /dev/partion

70. How to fix inssev warning when trying to use chkconfig:

    • update-rc.d -f <deamon> remove

    • update-rc.d -f <deamon> defaults

71. How to turn on/off DNS trace logging:

    • rndc querylog

72. Commandline speed test:

    • wget -O /dev/null http://speedtest.tele2.net/1GB.zip

73. Burn ISO or other images from commandline:

    • growisofs -Z /dev/cdrom=file.iso

74. Remove white space in all files in directory

    • for file in *; do  mv "$file" "${file//[[:space:]]}"; done

75. How to get UDID from iPhone:

    • lsusb -s :`lsusb | grep iPhone | cut -d ' ' -f 4 | sed 's/://'` -v | grep iSerial | awk '{print $3}'

76. How to remount read only drive live:

    • mount / -rw -o remount

77. How to sniff TFTP/DHCP requests:

    • tshark -i eth0 -f "tcp portrange 67-69" -V

78. Fix Debian keyring on the commandline:

    • apt-get install debian-keyring debian-archive-keyring

    • apt-key update

79. Test HDD read/write speeds:

    • hdparm -Tt /dev/sda

80. Kill all processes with pgrep

    • kill $(pgrep name)

81. Force user to change password in x amount of days:

    • chage -d {days} {username}

82. Change automatically expire user accounts in x amount of days:

    • usermod --expiredate={2015-06-01} {username}

83. Install KDE on Fedora Systems:

    • yum groupinstall "KDE Plasma Workspaces:"

84. Search for lines that do not match #. The first ^ refers to the beginning of the line. [^#;] means any character which is not # or ;

    • grep "^[^#;]" filename

85. Match two patterns using grep:

    • grep -E "string1|string2" filename