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 remove all symbolic link:

    • find -type l -delete

63. How to find device or partition block size:

    • blockdev --getbsz partition

64. How to convert KVM to VMWARE:

    • qemu-img convert -O vmdk filename.qcow2 filename.vmdk

65. List UUID of all disks:

    • ls /dev/disk/by-uuid -lt

66. Add CDROM to apt:

    • apt-cdrom add

67. Rebuild software RAID:

    • mdadm --assemble --scan

68. Time stamp on history command:

    • HISTTIMEFORMAT="%d/%m/%y %T " && history<pre>

69. Remount read/write:

    • mount -o remount, rw / 

70. Find port number of running application:

    • lsof -Pan -p {PID} -i

71. WAN IP Address from commandline:

    • curl -s ifconfig.co

72. Burn CD/DVD commandline:

    • growisofs -dvd-compat -Z /dev/cdrom=filename.iso

73. Bandwidth Test Commandline:

    • curl -s https://raw.githubusercontent.com/sivel/speedtest-cli/master/speedtest.py | python -

74. Fix E353: Nothing in register "

    • echo set clipboard=unnamed >> ~/.vimrc

75. Find Out Which Process Is Listening Upon a Port:

    • netstat -tulpn

76. Replace all spaces in files within a directory with an underscore:

    • for f in *\ *; do mv "$f" "${f// /_}"; done

77. Disk usage of all directories including hidden:

    • du -sch .[!.]* *

78. Check process by CPU and PID:

    • ps -eo pcpu,pid,user,args | sort -k 1 -r | head -10

79. Create simple HTTP server from present working directory:

    • python -m SimpleHTTPServer

80. Resize img file

    • qemu-img resize test.img 2G

81. a wk vertical to horizontal

    • awk 'ORS=" "' filename

82. Re-read partition table after modifications (SD or USB):

    • partprobe /dev/sdX

83. Find with max depth of 3 directories:

    • find -maxdepth 3

84. Find SCSI/SATA devices

    • lsscsi

85. ecm uncompress multiple files:

    • for i in *; do  ecm-uncompress "$i"; done

86. Force downgrade of package:

    • apt-get install apt=1.4.8 libapt-pkg5.0=1.4.8 apt-utils=1.4.8 libapt-inst2.0:amd64=1.4.8

87. Find package dependencies from repo:

    • debfoster -d package

88. List video drivers used. Search for "configuration":

    • dlshw -c video

89. List all listening network ports:

    • netstat -ntpl

90. Check ports using netcat:

    • nc -w 5 -zv {ipaddress} {port}

91. Show Debian/Ubuntu release information:

    • lsb_release  -a

92. Reinstall GRUB on drives after OS is running:

    • dpkg-reconfigure grub-pc

93. Cut example to get full names of users from passwd:

    • cut -d':' -f5 /etc/passwd

94. Deletes any trailing whitespace at the end of each line:

    • :%s/\s\+$//e

95. Check UDP port is open/closed:

    • map -sU -p port ip

96. Unlink all symbolic links in dir:

    • find . -type l -exec unlink {} \;

97. See process in memory:

    • ps wwu -C process

98. See process tree of all processes on system:

    • ps axjf

99. Sort processes memory from highest to lowest:

    • ps -o pid,user,%mem,command axf | sort -b -k3 -r

100. Sort processes CPU from highest to lowest:

     • ps -o pid,user,%cpu,command axf | sort -b -k3 -r

101. Display uncommented lines in a file:

     • cat {filename} | egrep -v "(^#.*|^$)"

102. List all process running on port number

     • lsof -i :8080

103. Show the time and date when Linux was first installed

     • ls -lact --full-time /etc |tail

104. Show SSL Cert information

     • curl --insecure -v https://www.google.com 2>&1 | awk 'BEGIN { cert=0 } /^\* Server certificate:/ { cert=1 } /^\*/ { if (cert) print }'

105. Find largest files by size

     • sudo find / -xdev  -type f -size +100M -exec ls -hla {} \; | sort -nk 5

106. Display SSL Cert expiry date.

     • openssl x509 -enddate -noout -in file.pem

107. Extract and reverse engineer .bin or .img files. Or any other binary:

     • binwalk --dd='.*' file.bin

108. Extract compressed file system:

     • 7z e filename