Unexpire an account and set it to never expire
# passwd -x -1 <account>
Tar commands
To create an archive using tar, use a command like this, which bundles all the files in the current directory that end with .txt into the alltxt.tar file: tar cvf alltxt.tar *.txt Here’s a second example, which creates a tar file named images.tar containing all the files from the images directory (and any of its…
Show disk usage in descending order
If you need to find the amount of disk space being consumed in Linux/Unix, you can show it recursively through your directories as follows. $ du -ks * | sort -gr 11927760 Library 7729280 Desktop 5408572 Music 118840 Downloads 99740 Pictures 79668 zabbix 74300 Documents 1048 Sites 856 Movies 300 Applications 228 macserv-snmpwalk.txt 8 yo_zimbra_template.xml…
MariaDB/MySQL – Recover root password
Here are commands you need to type for each step (login as the root user): Step 1. Stop MariaDB service. # systemctl stop mariadb Step 2. Start MariaDB server w/o password. # mariadb_safe –skip-grant-tables & [1] 5988 Starting mariadb daemon with databases from /var/lib/mysql mariadb_safe[6025]: started Step 3. Connect to mariadb server using mysql client: # mysql -u root…
MariaDB/MySQL – How to set up MySQL replication
Note: It is recommended to uninstall and then reinstall mysql and attendant packages on the slave if it has been used a a slave for replication previously. There may be a permissions or other issue which often brings up problems when bringing the slave back up upon reconfiguration if packages are not reinstalled. There may…
Generating and using RSA keys for SSH logins
Sometimes using an interactive SSH login to a remote system is not desired. For instance if you have created rsync scripts to automate backups of one system to another. A good way to automate this while maintaining a level of security is with the use of RSA encrypted keys shared between the machines you wish…
FTP – Read only access to user directory
VSFTPD is a great FTP server but sometimes it lacks the fine level control other FTP servers can offer. For instance, it does allow universal read only access to accounts but does not easily allow some home user accounts full access while others are more limited. There may be other solutions to this problem but…
Enabling sudo for users
Some users may need sudo access for executing root commands on Linux servers. It is a simple matter to allow users access to execute the sudo command. Add the user to the system in a regular fashion: # useradd <username> Edit the /etc/group file and add the new user to the wheel group. # vim…
Enable color coding when using the ls command
By default color coding is disabled for the ”’ls”’ command under Ubuntu. If you wish to enable it simply add the following to your ”’.bashrc”’ file alias ls=’ls –color=auto’ Note: This is different than enabling color coding under Mac OSX as documented. If you wish for color coding when using the ”’ls”’ command under Mac…
Crontab – How it is used
Crontab is a great utility to automate scripts and processes on your Linux/Unix/Mac machine. Regular users and root each have access to this utility. To check the cron jobs a particular user already has you can run the following from the command line. crontab -l This will list all current running cron jobs. Example: [root@web…