$ at 9am March 1
2. Schedule a queue to run after 5 minutes.
$ at now +5 minutes
3. Check any jobs pending to run, same as at -l .
$ atq
4. Empty out a file.
$ cat /dev/null > /path/to/file
5. Change directory, see also pushd and popd.
$ cd
6. List run level information for the service type.
$ chkconfig --list
7. Change owner recursively.
$ chown -R
8. Change shell.
$ chsh
9. Scan recursively for viruses.
$ clamscan -r
10. Compare two files.
$ cmp file1 file2
11. Copy keeping the directory structure.
$ cp --parent /source/path /destination/path
12. Copy keeping the permissions of the user.
$ cp -p
13. Copy recursive.
$ cp -r
14. Copy without shell aliasing.
$ \cp
15. List crontab for user.
$ crontab -u
16. Check current date and time.
$ date
17. Set current date and time, may need to set the hardware clock to the system time too, `man hwclock`.
$ date -s 'Wed May 28 11:35:00 EST 2003'
18. Show disk free in human readable format.
$ df -h
19. Configure interface using DHCP protocol.
$ dhclient eth0
20. Find context differences between two files.
$ diff -c
21. Creating a patch file.
$ diff -Naur oldDir/oldFile newDir/newFile > new_patchFile
22. Kernel buffer
$ dmesg
23. Show disk used in human readable format.
$ du -h /path/to/directory
24. Find files larger than 10MB.
$ find /path/to/file -size +10000k
25. Find file permissions with setuids.
find / \( -perm -4000 -o -perm -2000 \) -exec ls -ldb {} \;>> /tmp/suids
26. Search for world writable files and directories.
$ find / -perm -002
27. Display information on free and used memory.
$ free
28. Grep on word boundaries.
grep -w
29. Count the number of mathces - similar to “wc -l”.
$ grep -c
30. Perform timings of device reads for benchmark and comparison purposes.
$ hdparm -t /dev/hda1
31. Set the hardware clock to the current system time.
$ hwclock --systohc
32. check the ip address
$ ifconfig
33. Add an ip address to eth0.
$ ifconfig eth0:x xxx.xxx.xxx.xxx
34. Install loadable kernel module. You can also use `modprobe` to do the same.
$ insmod
35. Displays information about your system’s CPU and I/O.
$ iostat [ interval [ count ] ]
36. List iptables firewall rules in numeric format.
$ iptables -L -n
37. HangUP process so it will re-read the config file.
$ killall -HUP
38. Install the boot loader and increase verborsity.
$ lilo -v -v
39. Query the boot map.
$ lilo -q
40. One time boot to the named kernel.
$ lilo -R
41. Create symbolic link to the target file or directory.
$ ln -s
42. Configure dynamic linker run-time bindings
$ ldconfig
43. List the IPs bound via Ensim
$ listaliases
44. Quickly search for indexed files. Run `updatedb` to update the indexed database.
$ locate
45. List files.
$ ls
46. List loaded kernel modules
$ lsmod
47. Create the access.db file database map for sendmail.
$ makemap hash /etc/mail/access.db < /etc/mail/access
48. Create/Make a new directory.
$ mkdir
49. Generate a random 128 character length password.
$ mkpasswd -l 128
50. Read in the contents of your mbox (or the specified file).
$ mail -f /var/mail/nameOfFile
51. Print the mail queue
$ mailq
52.
$ mailstat /path/to/procmail/log
53. Description of the hierarchy directory structure of the system
$ man hier
54. Check the MD5 message digest.
$ md5sum
55. Mount points check.
$ mount
56. Provide information about your systems’ processor.
$ mpstat [ interval [ count ] ]
57.
$ ncftpget -R -u -p
hostname /local_dir /remote_dir
58.
$ netstat -a | grep -i listen
59. Will show you who is attached to what port.
$ netstat -anpe
60.
$ netstat -n
61. See which programs are listening on which port
$ netstat -lnp
62. Will show you what local TCP ports are open and what programs are running on them.
$ netstat -lntpe
63. Will show you what local UDP ports are open and what programs are running on them.
$ netstat -lnupe
64. Run a program with modified scheduling priority. (# range between -20 to +20, negative is higher priority)
$ nice -n # [command to nice]
65. Scan network
$ nmap -v hostname/ip
66. Patch and keep a backup
$ patch -p# -b < patch_file
67.
$ ps -ecaux
68. Turn off all quotas for users and groups, verbose mode
$ quotaoff -augv
69. Check quota for all users and groups interactively, do quotaoff first.
$ quotacheck -augmiv
70. Turn on all quotas for users and groups
$ quotaon -augv
71. Add host ip to route on a particular device.
$ route add -host xxx.xxx.xxx.xxx dev eth0:x
72.
$ rdate
73. Remove file
$ rm
74. Remove kernel module
$ rmmod
75. Display the routing table in numeric.
$ route -n
76.
$ rpm
77. Uninstall/erase package.
$ rpm -e
78. Erase without dependency check.
$ rpm -e --nodeps
79. List out installed rpms by date, latest on top.
$ rpm -qa --last | less
80. Rebuild rpm database.
$ rpm --rebuilddb
81. Find which package owns the file.
$ rpm -qf /path/to/file
$ rpm -q --whatprovides /path/to/file
82. Verify package.
$ rpm -V
or
$ rpm -Vf /path/to/file
83. Locate documentation for the package that owns the file.
$ rpm -qdf /path/to/file
84. Query information on package.
$ rpm -qip
85. Query files installed by package.
$ rpm -qlp
86. Gives list of files that will be installed/overwritten.
$ rpm -ql
87. Will show the scripts that will be executed.
$ rpm -q --scripts
88. Display system activity information
$ sar
89. Print a 0 padded sequence of numbers.
$ seq -w 1 10
90. Record eveything printed on your terminal screen.
$ script -a
Ctrl+D to exit out. `more
91. Check the status of a service.
$ service
92. Restart after shutdown and force fsck (fsck may take a while).
$ shutdown -rF now
93. Split a file into pieces with numeric suffixes, so it can be burnt to cds.
$ split -d -b 640k big_input_filename.gz piece_file_prefix.gz.
To piece it back you can `cat piece_file_prefix.gz.* > original.gz`
94. Determine if a network service binary is linked againt tcp wrapper, libwrap.a
$ strings -f
96. how to use tar
$ tar -cvzf fileName.tar.gz `find /file/path -mtime -1 ! -type d -print`
97.
$ tar -xvzpf fileName.tar.gz /path/to/file.txt
98. How to use tcpdump
$ tcpdump -i eth0 dst port 80 | more
99. System process status
$ top
100. View the full command line.
$ top -c
101. Create empty file of 0 byte
$ touch
102. Similar to `which` - shows full path to the command.
$ type
103. Check the limit of user
$ ulimit -a
104. Check the version of kernel running
$ uname -a
105. Update package profile with rhn
$ up2date -p
106. Install package via up2date.
$ up2date -i
107.
$ uptime
108.
$ usermod
109. Utility reports virtual memory statistics
$ vmstat [second interval] [no. of count]
110. Show who is logged on and what they are doing.
$ w
111. Periodically watch output of a command in full screen
$ watch '
112. Run and generate the apache reports using webalizer
$ webalizer -c /path/to/webalizer.conf
113. Recursive download of a url, converting links, no parent.
$ wget -r -k -np
114. Mirror, convert links, backup original, dynamic to html and output a “logFile”.
$ wget -m -k -K -E
115. Locate the binary, source, and manual page files for a command.
$ whereis
116. Shows the full path of command.
$ which
117. Show who is logged on.
$ who
118. Yum package updates
$ yum check-update -- check to see what updates are needed
$ yum info
$ yum update
119. Control jobs:
$ Ctrl-z -- suspend foreground job
$ jobs -- list jobs
$ bg -- send job to background
$ fg -- bring job to foreground
Free, facebook, tips, Links, blogging, Downloads, Google, facebookTips, money, news, apps, Social, Media, Website, Tricks, games, Android, software, PIctures, Internet, Security, Web, codes, Review, bloggers, SAMSUNG, Worldwide, Contest, Exitic, Phones, facebookTricks, hacking, London, Olympics, SEO, Youtube, iOS, Adsense, gadgets, iPHONE, widgets, Doodle, twitter, video, Deals, technology, Aircel, Airtel, iPAD, Angry, Birds, BSNL, TechLife, GMAIL, Idea, Microsoft, SmartPhones, Stress, Buster, Windows, Yahoo, Infolinks, Nokia, Scam, Uninor, browsers, Amazon, Euro, CUP, Chat, IDM, JOBS, Modem, Music, Reliance, Results, SSC, Tata, Docomo, bing, freebie, mobile, placements, AIEEE, AlertPay, Chrome, College, Competetive, Exam, Dehradun, Extension, FireFox, GPRS, HTC, IMPACT, Info, MTS, Mark, Zukerberg, Paypal, Promotional, Post, Torrent, UTU, Unlocking, VodaFone, Wall, Paper, apple, books, engineering, iCAR, iTunes, pinterest, rovio, AVG, Admit, Card, Adobe, Affiliate, Marketing, Akhilesh, Amul, Girl, BlackBerry, ChromeBook, Clixsense, Coupon, Digitallife, Discovery, Emoticons, Festival, GATE, GIMP, Income, Tax, International, JSS, JailBreaking, Kindle, Linux, Local, MAX, PAYNE, Mac, Mango, Memory, Speed, Nexus, Online, Shopping, Raakhi, Report, Rising, Stars, Sample, Science, Sony, Syllabus, TabletBooK, Teamviewer, Templates, Dark, Knight, Rises, USA, UPMT, Virgin, Xperia, ZTE, challan, counselling, course, btech, funny, iMOVE, registration
source:http://linuxpoison.blogspot.com/2008/09/135781757118230.html