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Category: System Administrator

Grub manual booting Linux

grub> set pager=1 grub> ls (…will list (hd0) (hd0,msdos2) (hd0,msdos1) and similar…) grub> ls (hd0,1) or (hd0,msdos2,1) or whatever-partition (…until you find the partition which contains /bin, /boot, /dev, etc…) grub> set root=(hd0,1) grub> linux /boot/vmlinuz-3.13.0–29-generic root=/dev/sda1 (…substitute your own kernel versions + disk partition, of course…) grub> initrd /boot/initrd.img-3.13.0–29-generic grub> boot Once this routine …

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Shell Script function to manage execution error

A simple shell script to manage execution error and display a meaningful message to the user This function was designed for Korn Shell *ksh93* and should be POSIX Compliant. Please message me if you have suggestion to make it better. ### Simple function to display separator character on the size of terminal width f_print_separator () …

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Shell Script function get password

How to securely get a password from a user in a POSIX Compliant Shell Script.   There is 2 ways to create a function to securely get password in a shell script. 1. ksh93 and bash compliant: read -rsp "contextual message" variable 2. POSIX Compliant: printf %s "contextual message"; stty -echo; read passwd; stty echo; …

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Korn Shell – Variables Quick Reference

Korn Shell – Variables Quick Reference Typeset type and attribute options -A Create an associative array. -En Represent the variable internally as a double-precision floating-point number; improves the efficiency of floating-point arithmetic. If n is given, it is the number of significant figures to use in output. Large numbers print in scientific notation: [-]d.ddde±dd. Smaller …

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Why is printf better than echo in Shell Scripting?

Basically, it’s a portability (and reliability) issue. Initially, echo didn’t accept any option and didn’t expand anything. All it was doing was outputting its arguments separated by a space character and terminated by a newline character. Now, someone thought it would be nice if we could do things like echo "\n\t" to output newline or …

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How to register Clone RHEL to RHN

How to register Clone RHEL to RHN In order to register a Clone RedHat Enteprise to RHN and avoid having duplicate entry, you need to reset the unique SystemID of your Clone RedHat Enterprise.   To do so, you will need to remove the file systemid which contain a unique identifier for your machine that RedHat …

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Install VMWare Tools on Fedora

Installing VMware Tools on Fedora A freshly installed Fedora 21 guest comes preinstalled with open-vm-tools, an open-source version of the VMware tools for guest operating systems.  However, these tools can’t do everything the proprietary version can; at least not on VMware Workstation.  So here’s the steps required to swap things out and install VMware Tools on …

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