Linux Cheatsheet

Linux Cheatsheet

Linux Cheatsheet is here just to not waste time when i will try to remember one of these commands.

1. Find all files changed in a certain range of time

To find all files modified on the 26 June, 2015:

$ find /home/user/docs/ -type f -newermt 2015-04-26 ! -newermt 2015-04-27

-newermt – modified files
-newerat – accessed files
-newerct – files which had their permission changed

2. Find files containing text

grep --include=\*.php -rnw /home/user/docs/ -e "birthday"

3. Get a number of files in a directory

ls -1 /home/user/docs/ | wc -l

4. Delete large number of files

rm does not help in this cause. Usually you will get smth like “/bin/rm: Argument list too long.”

find /home/user/docs/ -type f -delete

5. Change owner/group of files recursively

sudo chown -R www-data:www-data /home/user/docs/

6. Change permission of files recursively

sudo chmod -R 770 /home/user/docs/

7. Get folder size

du -hs /path/to/directory

-h is to get the numbers “human readable”, e.g. get 140M instead of 143260 (size in KBytes)
-s is for summary (otherwise you’ll get not only the size of the folder but also for everything in the folder separately)

8. Find files bigger than 100MB

find . -type f -size +100M

If you want the current dir only:

find . -maxdepth 1 -type f -size +100M

9. Working with iptables

add rule to block certain IP

iptables -A INPUT -s xx.xx.xx.xx -j DROP

insert rule to block IP into first line

iptables -I INPUT 1 -s xx.xx.xx.xx -j DROP

save current iptables rules to file

iptables-save > ip-tables

search for blocked IP address

iptables -L INPUT -v -n | grep xx.xx.xx.xx

list INPUT rules with line numbers

iptables -L INPUT -n --line-numbers

delete rule on line 3

iptables -D INPUT 3

To be updated…

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