The seq command prints a sequence of integers or real numbers, suitable for piping to other programs. The seq command can come in handy in various other commands and loops to generate sequence of numbers. The Syntax The general syntax of the “seq” command is: # seq [options] specification The examples 1. To simply print […]
Archives for January 2020
How to Install an Configure MASTER PDF EDITOR IN UBUNTU
Introduction In this article we are going to learn How to install master PDF editor in Ubuntu 16.04. master PDF editor is a open source free PDF editor application for Linux. It’s a light weight and user friendly application to use. This application is not only a PDF editor but more than that, you can […]
How to check and repair ACFS with FSCK
The Problem You noticed many inconsistencies in different asm metadata views, asmcmd and os outputs that are associated with the ACFS file system. Database shows corruption in RMAN or from dbverify. Database uses ACFS. ALTER DISKGROUP CHECK REPAIR comes back clean but you still see errors or check for corruption returns back positive, eg: $ […]
How to test a PHP script
PHP is a widely-used general-purpose scripting language that is especially suited for Web development and can be embedded into HTML. PHP runs on all major operating systems, from Unix variants including Linux, FreeBSD, Ubuntu, Debian, and Solaris to Windows and Mac OS X. It can be used with all leading web servers, including Apache, Nginx, […]
How to Set Space limits for MySQL for database/schema/table
MySQL itself has not such quotas, but it is possible to partially manage quota limitation at engine level. For MyISAM it is possible to limit table size using option myisam_data_pointer_size This variable limits default data pointer size: less this variable is, less rows would be allowed to be saved in the table. “Table is full” […]
How to Configure SSH to restrict Users/Groups with allow and deny directives
Question: How can we restrict user/group access to a system using ssh? SSH uses specific files for configuration to achieve these various restrictions. Inbound ssh sessions (into the host) are handled by sshd (the ssh daemon). This process has its own configuration file, /etc/ssh/sshd_config. The parameters in the /etc/ssh/sshd_config file that apply are AllowGroups, AllowUsers, […]
How to allow ssh with empty passwords in Linux
Question: How can we allow a user with empty password to login to a Linux system? Although it seems a risky requirement, but sometimes in a private, development environment this can come handy. Also openssh provides you with an option to have empty passwords for users while doing ssh. From the man page of sshd_config: […]
What is the difference between & (ampersand) and && (double ampersand) while executing simultaneous commands on Linux
To run more that one command simultaneously we can use the & (ampersand) special character. Another use of & is running the commands in the background. In that case though, you should use & once and the end of the command or script. For example: # [some command or script] & Using & (ampersand) to […]
What are Bash Exit Codes in Linux
What is an exit code Every script, command, or binary exits with a return code. You can see this value in the special variable $?. Return codes are numeric and are limited to being between 0-255 because an unsigned 8-bit integer is used. If you use a value of -1, it will return 255. Each […]
Downgrading an rpm package to a lower version (using “rpm” command)
Question: How to downgrade an rpm package in CentOS/RHEL 6 system to a lower version using the “rpm” command? Its not really recommended to use rpm command instead of yum to downgrade an rpm package. But in case if you don’t have a choice use the below procedure. Pre-requisites Make sure you have downloaded all […]