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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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diff files while disregarding indentation and trailing white space

Coping files, excluding certain files

Preserve file structure when coping and exclude some file o dir patterns

add all files not under version control to repository

With the force options the same results can be achieved

Replace Solaris vmstat numbers with human readable format

% cat ph-vmstat.awk # Return human readable numbers function hrnum(a) { b = a ; if (a > 1000000) { b = sprintf("%2.2fM", a/1000000) ; } else if (a > 1000) { b = sprintf("%2.2fK", a/1000) ; } return(b) ; } # Return human readable storage function hrstorage(a) { b = a ; if (a > 1024000) { b = sprintf("%2.2fG", a/1024/1024) ; } else if (a > 1024) { b = sprintf("%2.2fM", a/1024) ; } return(b) ; } OFS=" " ; $1 !~ /[0-9].*/ {print} $1 ~ /[0-9].*/ { $4 = hrstorage($4) ; $5 = hrstorage($5) ; $9 = hrnum($9) ; $10 = hrnum($10) ; $17 = hrnum($17) ; $18 = hrnum($18) ; $19 = hrnum($19) ; print ; }

Sum file sizes

Stop Flash from tracking everything you do.

Brute force way to block all LSO cookies on a Linux system with the non-free Flash browser plugin. Works just fine for my needs. Enjoy.

Replace spaces in a filename with hyphens

As long as you have perl based rename. You can check: =$ rename --help Unknown option: help Usage: rename [-v] [-n] [-f] perlexpr [filenames] That's the good one.

Clear history

a function to find the fastest free DNS server

Evoke from the command like as: $ timeDNS commandlinefu.com . This isn't too terribly practical, but it is a good code example of using subshells to run the queries in parallel and the use of an "anonymous function" (a/k/a "inline group") to group i/o. . I'm assuming you have already defined your local DNS cache as ${local_DNS}, (here, it's 192.168.0.1). . You do need to install `moreutils` to get `sponge`. . If you're willing to wait, a slower version w/o sponge, (and w/o sorting), is this: . DNS () { for x in "192.168.0.1" "208.67.222.222" "208.67.220.220" "198.153.192.1" "198.153.194.1" "156.154.70.1" "156.154.71.1" "8.8.8.8" "8.8.4.4"; do (echo -n "$x "; dig @"$x" "$*"|grep Query) ; done ; }

Recursive Ownership Change

Changing files ownership in a directory recursivley from a user to another

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