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Optimal way of deleting huge numbers of files

Using xargs is better than: find /path/to/dir -type f -exec rm \-f {} \; as the -exec switch uses a separate process for each remove. xargs splits the streamed files into more managable subsets so less processes are required.
This is sample output - yours may be different.
12

find /path/to/dir -type f -print0 | xargs -0 rm

root · 2009-01-26 11:30:47 62
Display PHP files that directly instantiate a given class

This greps all PHP files for a given classname and displays both the file and the usage. Show Sample Output
This is sample output - yours may be different.
```
tao/tests/filter/TestUrl.php:        $this->objFilter = new filter_Url();
tao/classes/local/view/Photos.php:        $objFilter  = new filter_Url();
```
1

find . -name "*.php" -exec grep \-H "new filter_" {} \;

root · 2009-01-26 10:43:09 73
Run the last command as root

Useful when you forget to use sudo for a command. "!!" grabs the last run command.
This is sample output - yours may be different.
1219

sudo !!

root · 2009-01-26 10:26:48 250
Creates a customized search command

Creates a command alias ('cr' in the above example) that searches the contents of files matching a set of file extensions (C & C++ source-code in the above example) recursively within the current directory. Search configured to be in colour, ignore-case, show line numbers and show 4 lines of context. Put in shell initialisation file of your choice. Trivially easy to use, e.g: cr sha1_init Show Sample Output
This is sample output - yours may be different.
```
./openssl/signatures.c-600-xmlSecOpenSSLDsaSha1EvpInit(EVP_MD_CTX *ctx)
./openssl/signatures.c-601-{
./openssl/signatures.c:602:    return SHA1_Init(ctx->md_data);
./openssl/signatures.c-603-}
./openssl/signatures.c-604-
--
./openssl/signatures.c-706-    NULL,
./openssl/signatures.c-707-#else /* XMLSEC_OPENSSL_096 */
./openssl/signatures.c:708:    SHA1_Init,
./openssl/signatures.c-709-    SHA1_Update,
./openssl/signatures.c-710-    SHA1_Final,
```
0

alias cr='find . 2>/dev/null -regex '\''.*\.$c\|cpp\|pc\|h\|hpp\|cc$$'\'' | xargs grep --color=always -ni -C2'

chrisdrew · 2009-01-26 08:54:25 56
Outputs a sorted list of disk usage to a text file

Recursively searches current directory and outputs sorted list of each directory's disk usage to a text file. Show Sample Output
This is sample output - yours may be different.
```
712     .
328     ./test
176     ./lib
144     ./doc
100     ./test/data
96      ./lib/rake
64      ./doc/release_notes
```
6

du | sort -gr > file_sizes

chrisdrew · 2009-01-26 01:12:54 62
Watch how fast the files in a drive are being deleted

This can be useful when a large remove operation is taking place.
This is sample output - yours may be different.
6

watch "df | grep /path/to/drive"

root · 2009-01-25 21:16:41 674
Execute a command at a given time

This is an alternative to cron which allows a one-off task to be scheduled for a certain time.
This is sample output - yours may be different.
266

echo "ls -l" | at midnight

root · 2009-01-25 21:07:42 85
Analyse an Apache access log for the most common IP addresses

This uses awk to grab the IP address from each request and then sorts and summarises the top 10.
This is sample output - yours may be different.
22

tail -10000 access_log | awk '{print $1}' | sort | uniq -c | sort -n | tail

root · 2009-01-25 21:01:52 47
Add SVN keywords property to all PHP and Javascript files
This is sample output - yours may be different.
3

find . $ -name "*.php" -o -name "*.js" $ -exec svn propset svn:keywords Id {} \;

root · 2009-01-24 00:54:35 63
Count files beneath current directory (including subfolders)
This is sample output - yours may be different.
18

find . -type f | wc -l

root · 2009-01-23 17:19:32 74

Display the top ten running processes - sorted by memory usage

ps returns all running processes which are then sorted by the 4th field in numerical order and the top 10 are sent to STDOUT. Show Sample Output

106

ps aux | sort -nk +4 | tail

root · 2009-01-23 17:12:33 294

Checks all MySQL tables

See http://dev.mysql.com/doc/refman/5.0/en/myisamchk.html for further details. You can also repair all tables by running: myisamchk -r *.MYI
This is sample output - yours may be different.
-2

myisamchk /path/to/mysql/files/*.MYI

root · 2009-01-22 10:20:00 133
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Change Windows Domain password from Linux

If you use Linux in a Windows domain and there are N days to expiry, this is how you can change it without resorting to a windows machine.

Display which user run process from given port name

automatically ditch old versions in a conflict

This is not exactly a commandline, but a vim macro to automatically ditch the "old" version of a conflict when dealing with the naster

convert binary data to shellcode

Periodically run a command without hangups, and send the output to your e-mail

Run "ps -x" (process status) in the background every hour (in this example). The outputs of both "nohup" and "ps -x" are sent to the e-mail (instead of nohup.out and stdout and stderr). If you like it, replace "ps -x" by the command of your choice, replace 3600 (1 hour) by the period of your choice. You can run the command in the loop any time by killing the sleep process. For example $ ps -x 2925 ? S 0:00.00 sh -c unzip E.zip >/dev/null 2>&1 11288 ? O 0:00.00 unzip E.zip 25428 ? I 0:00.00 sleep 3600 14346 pts/42- I 0:00.01 bash -c while true; do ps -x | mail (...); sleep 3600; done 643 pts/66 Ss 0:00.03 -bash 14124 pts/66 O+ 0:00.00 ps -x $ kill 25428 You have mail in /mail/(...)

Count lines of code across multiple file types, sorted by least amount of code to greatest

The same as the other two alternatives, but now less forking! Instead of using '\;' to mark the end of an -exec command in GNU find, you can simply use '+' and it'll run the command only once with all the files as arguments. This has two benefits over the xargs version: it's easier to read and spaces in the filesnames work automatically (no -print0). [Oh, and there's one less fork, if you care about such things. But, then again, one is equal to zero for sufficiently large values of zero.]

for newbies, how to get one line info about all /bin programs

Get simple description on each file from /bin dir, in list form, usefull for newbies.

Create an SSH connection (reverse tunnel) through your firewall.

Allows you to establish a tunnel (encapsulate packets) to your (Server B) remote server IP from your local host (Server A). On Server B you can then connect to port 2001 which will forward all packets (encapsulated) to port 22 on Server A. -- www.fir3net.com --

Google text-to-speech in local language or language of choice

Google text-to-speech in your local language or in language of choice via country code switch (ISO 639-1).

list files recursively by size

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