Find recently modified files
# find all files modified upto 1 day ago
find path -mtime +1
# exclude cache and css
find . -mtime +1 | grep -v -e cache -e css
# only look for index.php
find . -name '*.php' -mtime +1
Find files containing a string
grep word /var/www -r -l
grep 'several words' /var/www -r -l
Remove BOM
find . -type f -exec sed 's/^\xEF\xBB\xBF//' -i.bak {} \; -exec rm {}.bak \;
# Removes the 3 byte-order-marks ef bb bf from all files in all folders
Find large files
ncdu is also a very nice utility for this, du with a front end that lets you delete
du -hs * | grep M | sort -rn | head -n 10
cd /
du -hs
(look for a big directory and cd into it)
(repeat)
You can pipe du into grep to find just the GB or MB sized directories by:
du -hs * | grep G
... or
du -hs * | grep M
Example:
[[email protected] www]# cd /var/www/
[[email protected] www]# du -hs * | grep G
14G sites
where a normal du shows:
[[email protected] www]# du -hs *
8.0K cgi-bin
224K error
19M html
928K icons
5.6M manual
14G sites
76K usage
you can also get really tricky and....
[[email protected] var]# du -s * | sort -rn | head -n 10
14617056 www
4466176 lib
1009184 log
75460 cache
25012 spool
404 run
140 named
60 tmp
40 lock
32 empty
Which means
du -s * == Disk Usage, Summerize output
sort -rn == Sort, reverse order, numerical sorting
head -n 10 == Head of output, give me the top 10 lines
Find large folders
du --max-depth=0 * | sort -n
du -sh *
Find large files
# 10mb+ in current directory
find . -type f -size +10000k -exec ls -lh {} \; | awk '{ print $8 ": " $5 }'Rsync
rsync -avrz --progress $file_1 $file_2_with_wildcards* destination
rsync -avrz --progress [email protected]:/data/sites/war2 .
Database
rsync -avrz --progress war* ddo* [email protected]:/var/lib/mysql
Allow PHP to sudo commands
# visudo
Add
www-data ALL = NOPASSWD : ALL
Now PHP can
<?php
exec("sudo /etc/init.d/apache2 restart", $output);
echo implode("\n", $output);
?>
Firewall whitelist
List IPs
iptables -vL
Whitelist IPs to SFTP firewall
cd /etc
vim firewall.conf
iptables-restore < /etc/firewall.conf
To add more IP's to the port-22 allow list, edit /etc/firewall.conf and add the entries in there
Then apply the firewall settings
iptables-restore < /etc/firewall.conf
Whitelist IP to port 22
Look at denied sessions
tail -f /var/log/auth.log
vim /var/lib/denyhosts/allowed-hosts
/etc/init.d/denyhosts restart
IP should now be removed from
/etc/hosts.deny
Active sessions
Login times
# finger
Active domains
# who
Active IPs
# who --ips
Add users
adduser $user
vim /etc/group
Add $user after last : in www-data:x:33:
vim /etc/passwd
Change second number to 33 (www-data id)
cd /path/in/question
chown -hR $user:www-data .
Upgrade Java
apt-cache search java
apt-get update
apt-get install openjdk-6-jre-headless
-or-
apt-get install sun-java6-jre
update-java-alternatives --list
update-java-alternatives --set java-6-openjdk
^-- Or whatever you like!
Transfer files
wget -r ftp://username:[email protected]
wget -m ... (mirror)
Compress
# good compression, fast
tar -zcvf archive.tar.gz path
# extract
tar -zxvf archive.tar.gz
# best compression, slow
tar -jcvf archive.tar.bz2 path
# extract
tar -jxvf archive.tar.bz2
# no compression
tar -cvf archive.tar path
# extract
tar -xvf archive.tar
# zip, well-known but bad compression
zip -r archive.zip path
# unzip
unzip archive.zip
Disk info
$ df
File system disk space usage
$ df -h
Human readable (gb)
Memory info
$ free -m
Free memory in mb
Find and replace over all files
Recursively
find ./ -type f -exec sed -i 's/string1/string2/' {} \;
In same folder
perl -pi -w -e 's/search/replace/g;' *.php-e means execute the following line of code.
-i means edit in-place
-w write warnings
-p loopSee
http://www.liamdelahunty.com/tips/linux_search_and_replace_multiple_files.php
Find a file
find /path/ -name file.ext
find /path/ -iname file.ext
case-insensitive file
find . -iname .htaccess 2> /dev/null
hide errors
find . -iname '*whatever*' | grep -v 'regex_to_match_your_errors'
hide lines that contain text
Find a string in a file
egrep -r 'regex' ./dir_to_search
extended regular expression mode, supports more regexp syntax
egrep equivalent to grep -E
egrep -ir 'regex' ./dir_to_search_recursively
case insensitive
find . -iname '.htaccess' -exec grep -iE 'extended_regex' {} \;
{} placeholder
\; finishing argument in exec
find . -iname '.htaccess' -exec grep -iHE 'extended_regex' {} \;
-H show filename
Find a file containing a string
$ grep -H -r “string" /path
-r recurses into all subdirectories
-H prints the filename for each match
$ find /path/ -name file.ext -exec grep "string" {} \; -print
Find files modified since
find . -iname '*.php' -mtime -4 -print 2> /dev/null
Find which cron jobs are running
crontab -l
Restart Apache
/path/to/apache/bin/apachectl restart
Path
pwd
present working directory
Copy folder
cp -r folder destination/
Zip
zip -r file.zip path/*
Monitor slow MySQL queries
tail -f /var/log/mysql/mysql-slow.log
Monitors the file for appends and displays them
Works on any log file at all
tail -f is one of those necessary tools