Unix / Linux: Backup Restore Partition Table (MBR, EBR)
The partition table are most commonly associated with the Master Boot Record (MBR) and Extended Boot Record (EBR) on x86 systems. They are both 512 bytes long.
Tag Archives: unix
Unix / Linux: Sync Local Directories
To sync files between two local directories on Unix or Linux, you can either choose to perform a soft link to the source directory or use rsync or lsyncd daemon.
MySQL: Export Each Database to Individual SQL File
MySQL backups are normally done using mysqldump – a MySQL database backup program. The problem is all the backups will be written to a single output SQL file. I prefer to dump each MySQL database to a separate SQL file.
Shell Script: Check If Weekday
There are two ways to perform a “is it a weekday” logic in shell scripts. One way is to use cron. The other is to get the day of week from the date command.
Unix / Linux: Generate MD5 Checksum
The md5sum command can be used to generate MD5 checksums for a string or a file. This is installed by default on most Unix and Linux distributions.
Disable Nginx Version Number in HTTP Headers
By default, Nginx sends the version number in the HTTP response. Hackers can use this information to try and exploit any known vulnerabilities in Nginx, especially if you are running a version with known vulnerabilities. Security wise, it’s a good practice to not reveal versions numbers of the HTTP server.
Unix / Linux: Run Cron Jobs on Last Day of Month
Cron jobs can be scheduled based on minute, hour, day of month, month or by the day of the week. Flexible as it may seem, there is actually no simple way to schedule a job to be run on the last day of every month.
Shell Script: Get Epoch Time
Unix time, POSIX time or Epoch time is defined as the number of seconds that have elapsed since 00:00:00 January 1, 1970 UTC. There are a few methods to retrieve the Epoch time on Unix and Linux.
UNIX / Linux: Get External IP from Command Line
If you are behind a NAT router or firewall and if you need to know the external IP address on a UNIX or Linux workstation, the below one liners may be of help.
UNIX / Linux: File Permissions in Octal
To set file permissions using the chmod command, we can specify the permissions in either numeric mode or symbolic mode. But when we want to get the file permissions, most often with the ls -l command, we are normally only given a printout using the symbolic mode.
