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Time Synchronisation with NTP
This is sample output - yours may be different.
2

ntpdate ntp.ubuntu.com pool.ntp.org

fitidavid · 2009-03-20 12:40:31 7
Sort files by size
This is sample output - yours may be different.
5

ls -l | sort -nk5

lme · 2009-03-20 12:28:34 39
Place the argument of the most recent command on the shell

When typing out long arguments, such as: cp file.txt /var/www/wp-content/uploads/2009/03/ You can put that argument on your command line by holding down the ALT key and pressing the period '.' or by pressing <ESC> then the period '.'. For example: cd 'ALT+.' would put '/var/www/wp-content/uploads/2009/03/ as my argument. Keeping pressing 'ALT+.' to cycle through arguments of your commands starting from most recent to oldest. This can save a ton of typing.
This is sample output - yours may be different.
351

'ALT+.' or '<ESC> .'

atoponce · 2009-03-20 11:36:04 84
Revert back all files currently checked out by Perforce SCM for edit
This is sample output - yours may be different.
1

ropened='p4 opened | awk -F# "{print \$1}" | p4 -x - revert'

Alexander · 2009-03-20 11:10:47 5
Print the list of all files checked out by Perforce SCM

Just type 'opened' and get all files currently opened for edit.
This is sample output - yours may be different.
0

alias opened='p4 opened | awk -F# "{print \$1}"'

Alexander · 2009-03-20 11:06:41 14
print date 24 hours ago
This is sample output - yours may be different.
4

date --date=yesterday

KeePon · 2009-03-20 10:56:32 7
Alias for displaying a process tree nicely

By 'pst' you can print out process tree with all details about all processes (including a command line, PID, and the current process you are running in). By 'pst username' you can get an information about processes belonging to the particular user 'username'. Show Sample Output
This is sample output - yours may be different.
```
...
  |-(events/6,32)
  |-(events/7,33)
  |-gam_server,3914
  |-gdm-binary,4670 -nodaemon
  |   `-gdm-binary,4766 -nodaemon
  |       |-Xorg,4771 :0 -br -audit 0 -auth /var/gdm/:0.Xauth -nolisten tcp vt7
  |       `-gdmgreeter,4786
  |-gdm-rh-security,4768
...
```
0

alias pst='pstree -Alpha'

Alexander · 2009-03-20 10:53:37 5
Quicker move to parent directory

Alias two dots to move to parent directory. Put it into your .bashrc or .profile file. Show Sample Output
This is sample output - yours may be different.
```
~/foo/ $ ..
~/ $
```
9

alias ..='cd ..'

eimantas · 2009-03-20 09:57:28 8
Gets the last string of previous command with !$

It helps you save a lot of writing :-) Show Sample Output
This is sample output - yours may be different.
```
vi abc.txt -> $cat !$ -> $ls -al !$
```
4

$mkdir mydir -> mv !$ yourdir -> $cd !$

Bluehive · 2009-03-20 09:00:28 12
Leave a comment when voting down..

I think it would be wise if anyone voting down left a comment indicating the reason for that action. Don't keep it to yourself. Thanks. Show Sample Output
This is sample output - yours may be different.
```
I voted down because <reason_for_voting_down>
```
-10

if [ "${vote}" = "down" ]; then echo leave comment; fi

JesusSuperstar · 2009-03-20 00:31:13 187
Count number of bytes that are different between 2 binary files
This is sample output - yours may be different.
1

cmp -l file1.bin file2.bin | wc -l

thallett · 2009-03-20 00:21:22 4
Show directories in the PATH, one per line

The output of "echo $PATH" is hard to read, this is much easier. The parentheses ensure that the change to the input field separator (IFS) only happens the the sub shell and not affecting the current shell. Show Sample Output
This is sample output - yours may be different.
```
/bin
/usr/X11R6/bin
/usr/sbin
/sbin
/usr/bin
.
```
3

( IFS=:; for p in $PATH; do echo $p; done )

haivu · 2009-03-19 22:45:47 8
Store mp3 playlist on variable and play with mpg123

On my music directory, I create variable that contains all mp3s files, then I play them with mpg123. -C options enable terminal control key, s for stop, p for pause, f for forward to next song.
This is sample output - yours may be different.
-1

PLAYLIST=$(ls -1) ; mpg123 -C $PLAYLIST

servermanaged · 2009-03-19 17:20:28 12
Add a line for your username in the /etc/sudoers file, allowing you to sudo in Fedora

I am new to linux, and I was trying to figure out why I could not sudo with my username in Fedora 10. This command, when run as root, will add a line to the sudoers file allowing the loginname supplied to sudo. The above line will require a password when you sudo, if you wish to sudo without password, use: echo 'loginname ALL=(ALL) NOPASSWD:ALL' >> /etc/sudoers instead. you have to run this command as su, and this is just an easier way of using visudo, just adds it right from the terminal.
This is sample output - yours may be different.
-14

echo 'loginname ALL=(ALL) ALL' >> /etc/sudoers

refrax · 2009-03-19 13:23:43 21
How many world writeable files on your system? (Mandriva Linux msec)

Mandriva Linux includes a security tool called "msec" (configurable via "draksec"). One of the many things it regularily checks for is world writeable files. If any are found, it writes the list to /var/log/security/writable.today. "wc -l" simply counts the number of lines in the file. This number should be low. Browse through /var/log/security/writable.today and consider if any of those files *need* to be world-writeable (and if not, modify the permissions. eg: "chmod o-w $file"). A large number of world-writeable files may indicate that umask is not correctly set in /etc/profile (or ${HOME}/.bash_profile) but could also indicate poor security configuration or even malicious activity. Show Sample Output
This is sample output - yours may be different.
```
# wc -l /var/log/security/writable.today
7 /var/log/security/writable.today
```
0

# wc -l /var/log/security/writable.today

mpb · 2009-03-19 12:25:52 7
find the longest command in your history
This is sample output - yours may be different.
3

history | perl -lane '$lsize{$_} = scalar(@F); if($longest<$lsize{$_}) { $longest = $lsize{$_}; print "$_"; };' | tail -n1

salparadise · 2009-03-19 02:52:30 6
Update your journal

prerequisite: mkdir ~/journal
This is sample output - yours may be different.
1

vi ~/journal/$(date +%F)

ar · 2009-03-18 23:31:13 4
colored prompt

It colors the machine name and current directory different colors for easy viewing.
This is sample output - yours may be different.
5

export PS1='\[\033[0;35m\]\h\[\033[0;33m\] \w\[\033[00m\]: '

kamiller · 2009-03-18 22:05:48 11
List the largest directories & subdirectoties in the current directory sorted from largest to smallest.
This is sample output - yours may be different.
8

du -k | sort -r -n | more

puddleglum · 2009-03-18 18:14:19 7
Clear the terminal screen
This is sample output - yours may be different.
191

ctrl-l

mrttlemonde · 2009-03-18 17:38:49 553
Decreasing the cdrom device speed

Decreasing the cdrom device speed may be more comfortable to watch films (for example)
This is sample output - yours may be different.
8

eject -x 4

mrttlemonde · 2009-03-18 16:25:11 6
Scan for new SCSI devices

Issues a scan command on the given scsi host adapter (ex. a fibre channel adapter, in the example above on host0). Output can be watched in the messages log or in "dmesg"
This is sample output - yours may be different.
3

echo "- - -" > /sys/class/scsi_host/host0/scan

angrox · 2009-03-18 15:26:42 9
Lists architecture of installed RPMs

Lists all installed RPM packages with name and architecture, which is useful to check for compability packages (+ required i386 packages) on a 64bit system. Show Sample Output
This is sample output - yours may be different.
```
sgml-skel noarch
update-alternatives noarch
desktop-file-utils x86_64
db-devel x86_64
```
2

rpm -qa --queryformat "%{NAME} %{ARCH}\n"

angrox · 2009-03-18 15:19:21 13
Resets terminal in its original state

Resets a scrambled terminal into its orignal state.
This is sample output - yours may be different.
0

^[c (ctrl-v esc-c)

angrox · 2009-03-18 15:15:24 13
Doing some floating point calculations with rounding (e.g. at the 3rd decimal)
This is sample output - yours may be different.
1

echo '123/7' |bc -l |xargs printf "%.3f\n"

mrttlemonde · 2009-03-18 14:20:32 5
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Capture video of a linux desktop

Monitor a file with tail with timestamps added

Look for English words in /dev/urandom

* to get the English dictionary: wget http://www.mavi1.org/web_security/wordlists/webster-dictionary.txt

Apply fade effect to a audio

fade [type] fade-in-length [stop-time [fade-out-length]] Apply a fade effect to the beginning, end, or both of the audio. An optional type can be specified to select the shape of the fade curve: q for quarter of a sine wave, h for half a sine wave, t for linear (`triangular') slope, l for logarithmic, and p for inverted parabola. The default is logarithmic. A fade-in starts from the first sample and ramps the signal level from 0 to full volume over fade-in-length sec? onds. Specify 0 seconds if no fade-in is wanted. For fade-outs, the audio will be truncated at stop-time and the signal level will be ramped from full volume down to 0 starting at fade-out-length seconds before the stop-time. If fade-out-length is not specified, it defaults to the same value as fade-in-length. No fade-out is performed if stop-time is not specified. If the file length can be determined from the input file header and length-changing effects are not in effect, then 0 may be specified for stop-time to indicate the usual case of a fade-out that ends at the end of the input audio stream. All times can be specified in either periods of time or sample counts. To specify time periods use the format hh:mm:ss.frac format. To specify using sample counts, specify the number of samples and append the letter `s' to the sample count (for example `8000s').

shutdown if wget exit

check open ports without netstat or lsof

Commit command to history file immedeately after execution

This could be added to .bashrc. Background: Linux usually saves history only on clean exit of shell. If shell ends unclean, history is lost. Also numerous terminals might confuse their history. With this variable set, history is immedeately written, accessible to all other open shells.

list block devices

Shows all block devices in a tree with descruptions of what they are.

print the name of each package APT knows [matching a prefix]

In this case, linux- is the prefix; simply running $apt-cache pkgnames would list every package APT knows about. The default APT config assumes -g, --generate; to use the cache as/is, you could similarly run: $apt-cache --no-generate pkgnames [prefix] Adding --all-names, like so: $apt-cache --no-generate --all-names pkgnames [prefix] would print all the packages APT knows about, using the cache as/is, including virtual packages and missing dependencies. This command was shamelessly stolen from the apt-cache(8) man-page.

Convert seconds to [DD:][HH:]MM:SS

Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

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