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Copy via tar pipe while preserving file permissions (cp does not!; run this command with root!)

cp options: -p will preserve the file mode, ownership, and timestamps -r will copy files recursively also, if you want to keep symlinks in addition to the above: use the -a/--archive option
This is sample output - yours may be different.
4

cp -pr olddirectory newdirectory

stanishjohnd · 2009-08-22 22:11:24 8
Download Youtube Playlist

This will download a Youtube playlist and mostly anything http://code.google.com/apis/youtube/2.0/reference.html#Video_Feeds The files will be saved by $id.flv
This is sample output - yours may be different.
3

y=http://www.youtube.com;for i in $(curl -s $f|grep -o "url='$y/watch?v=[^']*'");do d=$(echo $i|sed "s|url\='$y/watch?v=$.*$&.*'|\1|");wget -O $d.flv "$y/get_video.php?video_id=$d&t=$(curl -s "$y/watch?v=$d"|sed -n 's/.* "t": "$[^"]*$",.*/\1/p')";done

matthewbauer · 2009-08-22 21:31:29 53
YES = NO
This is sample output - yours may be different.
4

yes n

elzapp · 2009-08-22 20:32:23 116
Copy via tar pipe while preserving file permissions (run this command as root!)

It's the same like 'cp -p' if available. It's faster over networks than scp. If you have to copy gigs of data you could also use netcat and the tar -z option in conjunction -- on the receiving end do: # nc -l 7000 | tar -xzvpf - ...and on the sending end do: # tar -czf - * | nc otherhost 7000
This is sample output - yours may be different.
1

tar -C /oldirectory -cvpf - . | tar -C /newdirector -xvf -

Cowboy · 2009-08-22 20:05:49 5
Print a random 8 digit number
This is sample output - yours may be different.
5

jot -r -n 8 0 9 | rs -g 0

curiousstranger · 2009-08-22 19:31:17 6
watch iptables counters

This will allow you to watch as matches occur in real-time. To filter out only ACCEPT, DROP, LOG..etc, then run the following command: watch 'iptables -nvL | grep -v "0 0" && grep "ACCEPT"' The -v is used to do an inverted filter. ie. NOT "0 0"
This is sample output - yours may be different.
7

watch --interval 0 'iptables -nvL | grep -v "0 0"'

Code_Bleu · 2009-08-22 18:18:05 51
Verbosely delete files matching specific name pattern, older than 15 days.
This is sample output - yours may be different.
6

find /backup/directory -name "FILENAME_*" -mtime +15 | xargs rm -vf

monkeymac · 2009-08-22 16:58:23 6
Remove empty directories

It only works in zsh
This is sample output - yours may be different.
1

rmdir **/*(/^F)

unixmonkey5248 · 2009-08-22 12:31:55 3
Cleanup firefox's database.

Sqlite database keeps collecting cruft as time passes, which can be cleaned by the 'vacuum;' command. This command cleans up the cruft in all sqlite files relating to the user you have logged in as. This command has to be run when firefox is not running, or it will exit displaying the pid of the firefox running.
This is sample output - yours may be different.
11

pgrep -u `id -u` firefox-bin || find ~/.mozilla/firefox -name '*.sqlite'|(while read -e f; do echo 'vacuum;'|sqlite3 "$f" ; done)

kamathln · 2009-08-22 10:36:05 10
List files and sizes

List files and sizes
This is sample output - yours may be different.
0

find / -type f -exec wc -c {} \; | sort -nr | head -100

hemanth · 2009-08-22 09:38:44 10
Reverse DNS lookups

Reverse DNS lookups, from a file with list of IP's, here the file is called lookups.txt
This is sample output - yours may be different.
-1

sed 's/$[0-9]*$\.$[0-9]*$\.$[0-9]*$\.$[0-9]*$.in-addr.arpa domain name pointer$.*$\./\4.\3.\2.\1\5/' \ lookups.txt

hemanth · 2009-08-22 09:37:20 4
Ping sweep without NMAP

Ping sweep without NMAP
This is sample output - yours may be different.
3

for i in `seq 1 255`; do ping -c 1 10.10.10.$i | tr \\n ' ' | awk '/1 received/ {print $2}'; done

hemanth · 2009-08-22 09:34:27 12
DNS cache snooping

DNS cache snooping
This is sample output - yours may be different.
0

for i in `cat names.txt`; do host -r $i [nameserver]; done

hemanth · 2009-08-22 09:26:31 3

Show account security settings Show Sample Output

chage -l <user>

hemanth · 2009-08-22 09:12:03 6

List all groups and the user names that were in each group

"cut" the user names from /etc/passwd and then running a loop over them. Show Sample Output
This is sample output - yours may be different.
```
avahi-autoipd:avahi-autoipd
avahi:avahi
backup:backup
bin:bin
daemon:daemon
debian-tor:debian-tor
debian-transmission:debian-transmission
games:games
gdm:gdm
gnats:gnats
haldaemon:haldaemon
```
3

for u in `cut -f1 -d: /etc/passwd`; do echo -n $u:; groups $u; done | sort

hemanth · 2009-08-22 09:06:02 7
Remove empty directories

You can also use, $ find . -depth -type d -exec rmdir {} \; 2>/dev/null
This is sample output - yours may be different.
6

find . -type d -empty -delete

hemanth · 2009-08-22 09:03:14 8
Random number generation within a range N, here N=10
This is sample output - yours may be different.
3

echo $(( $RANDOM % 10 + 1 ))

hemanth · 2009-08-22 08:57:01 5
power off system in X hours form the current time, here X=2
This is sample output - yours may be different.
1

echo init 0 | at now + 2 hours

hemanth · 2009-08-22 08:10:46 3
Day Date Time> Instead of $ or # at the terminal
This is sample output - yours may be different.
-1

export PS1='\D{%a %D %T}> '

hemanth · 2009-08-22 08:07:47 4
check open ports

Tested in Linux and OSX Show Sample Output
This is sample output - yours may be different.
```
kopete  1782   user   18u  IPv4  12568      0t0  TCP *:8010 (LISTEN)
sshd    2215   root    3u  IPv4  35583      0t0  TCP *:22 (LISTEN)
```
19

lsof -Pni4 | grep LISTEN

evenme · 2009-08-21 22:51:41 74
purge old stale messages on a qmail queue
This is sample output - yours may be different.
0

for i in `grep "unable to stat" /var/log/syslog | cut -d "/" -f 3 | sort | uniq`; do find /var/qmail/queue -name $i -type f -exec rm -v {} \; ; done

foob4r · 2009-08-21 22:03:39 3
delete all DrWeb status, failure and other messages on a postfix server
This is sample output - yours may be different.
0

mailq | grep DrWEB | awk {'print $1'} | sed s/*//g | postsuper -d -

foob4r · 2009-08-21 22:01:41 3
less an message on a postfix mailsystem with a specific message-id
This is sample output - yours may be different.
0

id=<XXXX>; find /var/spool/postfix/ -name $id -exec less {} \;

foob4r · 2009-08-21 21:58:58 3
replace old htaccess php AddHandler values with new one

Alter "AddHandler php5-cgi .php" and "AddHandler php4-cgi .php" entries to new "AddHandler x-httpd-php5 .php" respective php4 entries in all .htaccess files under /var/www Show Sample Output
This is sample output - yours may be different.
```
-
```
0

find /var/www/ -type f -name ".htaccess" -exec perl -pi -e 's/AddHandler[\s]*php(4|5)-cgi/AddHandler x-httpd-php\1/' {} \;

foob4r · 2009-08-21 21:55:22 3
floating point operations in shell scripts

allows you to use floating point operations in shell scripts Show Sample Output
This is sample output - yours may be different.
```
.6000
```
3

echo "scale=4; 3 / 5" | bc

foob4r · 2009-08-21 21:51:46 3
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vi show line numbers

you don't have to spell out numbers, you can just use nu

Test load balancers

With the "--resolve" switch, you can avoid doing DNS lookups or edit the /etc/hosts file, by providing the IP address for a domain directly. Useful if you have many servers with different IP addresses behind a load balancer. Of course, you would loop it: $ for IP in 10.11.0.{1..10}; do curl --resolve subdomain.example.com:80:$IP subdomain.example.com -I -s; done

Get a list of IP Addresses that have failed to login via SSH

This command shows a sorted list of the IP addresses from which there have been authentication errors via SSH (possible script kiddies trying to gain access to your server), it eliminates duplicates so it's easier to read, but you can remove the "uniq" command at the end, or even do a "uniq -c" to have a count of how many times each IP address shows in the log (the path to the log may vary from system to system)

Update grub menu.lst

Remove all commented lines Remove all blank lines Show the menu Up the delay so you have enough time to select a kernel Remove the quiet so you can watch the entire boot Add a rootdelay for san attached storage booting

translate with google, get all translations

the google-api gives you only one translation which is sometimes insufficent. this function gives you all translations, so you can choose which one fits best.

Intercept, monitor and manipulate a TCP connection.

This will handle multiple incoming connections. Also, found sed works best with -u flag (unbuffered io). Easiest way I've found to get ncat is to install nmap.

power off system in X hours form the current time, here X=2

Rolling upgrades via aptitude

This has been my "sysupgrade" alias since ca. 2006, first used on Debian Sid, then Sabayon, and it still does its duty on Mint nowadays without breaking stuff.

Donwload media from *.rm from an url of type htttp://.../*.ram

keep a log of the active windows

This logs the titles of the active windows, thus you can monitor what you have done during which times. (it is not hard to also log the executable name, but then it is gets too long)

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