Category: Linux

Find the files that is older than 30 days:
find . -atime +30 -exec stat -c “%n %y” {} \;

Delete the files that is older than 30 days:
find . -atime +30 -print0 | xargs -0 -r rm

Reference: https://stackoverflow.com/a/21451441/126639

crontab -e

Add the below line to the top.
MAILTO=””

chage -M number-of-days username

wget -t 1 –timeout=900 xxxxx

Reference:
https://stackoverflow.com/questions/2291524/does-wget-timeout

:set encoding=utf-8

Show user list
cat /etc/passwd

Show user’s group
id USER_NAME

Add user
adduser USER_NAME

Add group
groupadd GROUP_NAME

Assign user to a primary group (Require re-login to apply the new group)
usermod -g GROUP_NAME USER_NAME

Assign user to a secondary group
usermod -a -G GROUP_NAME USER_NAME

Turn on setgid bit (all new files and subdirectories created within the current directory inherit the group ID of the directory, rather than the primary group ID of the user who created the file)
chmod g+s .

Turn off setgid bit
chmod g-s .

Check if setgid is on
ls .
(If it is on, the group permission will become rws instead of rwx)

Lock an account
usermod –lock –expiredate 1970-01-02 username

Check lock status
sudo passwd -S username

Problem:
imuxsock begins to drop messages from pid due to rate-limiting

Solution:
vim /etc/rsyslog.conf
$SystemLogRateLimitInterval 60
$SystemLogRateLimitBurst 3000

/etc/init.d/rsyslog restart

Reference:
http://navyaijm.blog.51cto.com/4647068/1212042
http://www.rsyslog.com/tag/rate-limiting/

echo ‘export HISTTIMEFORMAT=”%d/%m/%y %T “‘ >> ~/.bashrc
source ~/.bashrc

Problem:
perl: warning: Setting locale failed.

Solution:
export LANGUAGE=en_US.UTF-8
export LC_ALL=en_US.UTF-8
export LANG=en_US.UTF-8
export LC_TYPE=en_US.UTF-8