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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 63
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 10:26:48 262
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 17:12:33 295

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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Rename files in batch

truncate deleted files from lsof

While the posted solution works, I'm a bit uneasy about the "%d" part. This would be hyper-correct approach: $ lsof|gawk '$4~/txt/{next};/REG.*$deleted$$/{sub(/.$/,"",$4);printf ">/proc/%s/fd/%s\n", $2,$4}' Oh, and you gotta pipe the result to sh if you want it to actually trim the files. ;) Btw, this approach also removes false negatives (OP's command skips any deleted files with "txt" in their name).

Execute a sudo command remotely, without displaying the password

The ssh command alone will execute the sudo command remotely, but the password will be visible in the terminal as you type it. The two stty commands disable the terminal from echoing the password back to you, which makes the remote sudo act as it does locally.

Remove ( color / special / escape / ANSI ) codes, from text, with sed

Remove ( color / special / escape / ANSI ) codes, from text, with sed Credit to the original folks who I've copied this command from. The diff here is: Theirs: [m|K] Theirs is supposed to remove \E[NUMBERS;NUMBERS[m OR K] This statement is incorrect in 2 ways. 1. The letters m and K are two of more than 20+ possible letters that can end these sequences. 2. Inside []'s , OR is already assumed, so they are also looking for sequences ending with | which is not correct. This : [a-zA-Z] This resolves the "OR" issue noted above, and takes care of all sequences, as they all end with a lower or upper cased letter. This ensures 100% of any escape code 'mess' is removed.

Pretty-print user/group info for a given user

rsync with progress bar.

transfer files from localhost to a remotehost.

quickly backup or copy a file with bash

less symbols, tab completion. including # export SIMPLE_BACKUP_SUFFIX="_`date +%F`" in your .bashrc provides you to easily timestamp your files

Recursive search inside the content of files under current directory - then view the result paginated with 'less'

This command will traverse all of the folders and subfolders under current working directory. For every file inside it, it will do a search inside the content of the file for a specific term 'what'. Then it will print a list of the lines that contain that term (and match that pattern). Each matching line will be preceded with the path and name to the file and then the line number iside taht file wehre the pattern was found. Then the actual content of the matching lien will be printed. The output will be piped throug less, so that the user can scroll through it if it goes beyond the limits of the current display window.

list files in mtime order

Simple but useful; list files in the current directory in mtime order. Useful if you've been working on something and then take a day or two off.

Number of CPU's in a system

/proc/cpuinfo contains information about the CPU. Search for "processor" in the /proc/cpuinfo file wc -l, counts the number of lines.

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