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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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commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

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Move all comments the top of the file in vim

Python comments begin with a #. Modify to suit other languages. Other uses: Instead of m0 use m$ for end of file or d for deleting all comments.

Replace underscores with spaces in filenames and dirnames, recursively into subdirs.

Everyone wants to take spaces out of filenames. Forget that. I want to put them back in. We've got tools and filesystems that support spaces, they look better, so I'm going to use them. Because of how find works I find I need to run this multiple times, if it's renaming subdirs. But it can be re-run without issues. I got this version of the command from a comment in this underscore-generating command. http://www.commandlinefu.com/commands/view/760/find-recursively-from-current-directory-down-files-and-directories-whose-names-contain-single-or-multiple-whitespaces-and-replace-each-such-occurrence-with-a-single-underscore. All I did was change the regex.

Create a zip file ignoring .svn files

Checks throughput between two nodes

This will show the throughput between two nodes. Thanks to szboardstretcher, who posted it here: http://www.linuxquestions.org/questions/linux-networking-3/quick-and-easy-way-to-measure-throughput-between-two-nodes-868998/

Display a random crass ascii art from www.asciiartfarts.com

Optionally, pipe the output into http://sed.sourceforge.net/grabbag/scripts/html2iso.sed Or: wget -qO - http://www.asciiartfarts.com/random.cgi | sed -n '//,//p' | sed -n '/

Compare / diff two images

Outputs the number of different pixels. 2 params to increase tolerance: * thumbnails size * fuzz, the color distance tolerance See http://en.positon.org/post/Compare-/-diff-between-two-images for more details.

Get the absolute path of a file

Screenshot pipe to remote host, adding URL to clipboard, notifying when done. (without saving locally)

Requires you to have password free login to remote host ;) Requires xclip and notify-send (If you want to put into clipboard and be notified when action is completed). DATE=$(date +%Y-%m-%d_%H-%M-%S)-$(($(date +%N)/10000000)); HOST="ssh host of your choice"; DEST="destination folder without trailing slash"; URL="URL for file if uploaded to web enabled dir ie. http://$HOST/~user/screenshot_$DATE.png"; import -window root png:- | ssh $HOST "cat > $DEST/screenshot_$DATE.png"; echo $URL | xclip; notify-send -u low "Screenshot Taken" "Entire screen.\nCopied to clipboard"

Capitalize the first letter of every word

Get the Volume labels all bitlocker volumes had before being encrypted

Get information of volume labels of bitlocker volumes, even if they are encrypted and locked (no access to filesystem, no password provided). Note that the volume labels can have spaces, but only if you name then before encryption. Renaming a bitlocker partition after being encrypted does not have the same effect as doing it before.

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