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cron Error: bad username; while reading /etc/cron.d file on Linux

I am getting the following error in my cron job log file /var/log/cron.log:
       Aug 22 01:59:01 server2 cron[7510]: Error: bad username; while reading /etc/cron.d/backups
I have job entry as follows to run a job at 00:50 every day for root user:
       50 0 * * * /etc/cron.d/backups
How do I fix this problem on Linux or Unix-like system?
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How to make disk image with dd on Linux or Unix

How do I create disk image using dd command? How do I perform disk cloning from a live Linux cd for backup or recovery purpose?
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Linux how long a process has been running?

I‘m a new Linux system user. How do I check how long a process or pid has been running on my Ubuntu Linux server?
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How to determine Linux guest VM virtualization technology

I have a cloud-based virtual machine running Ubuntu and CentOS Linux server. It may or may not be virtualized. How do I determine what kind of virtualization technology (VMWARE/ KVM/ XEN/ VirtualBox/ Container/ lxc/Hyper-V etc.) a Linux guest system running on? How do I find out the virtualization type of a CentOS 7 Linux VPS?
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Linux Iptables Delete postrouting Rule Command

I am a new Linux server sysadmin. I need to delete POSTROUTING rule. How do I delete postrouting rule on Linux server?
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How to gzip and keep original file on Unix or Linux command line

I would like to compress a log file using gzip Unix command line utility, and I would also like to keep the original file. However, when I use the gzip my-app.log command, results in modifying my log file and renaming it my-app.log.gz. How do I force the gzip command to keep original file while maintaining the original file on Linux or Unix-like system?
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How to copy permissions from one file to another on Linux

I need to copy or clone file ownership and permissions from another file on Linux. Is there a bash command line option to clone the user, group ownership and permissions on a file from another file on Linux operating system?
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A stack-based critical buffer overflow was found in the way the libresolv library (glibc) performed dual A/AAAA DNS queries. A remote attacker could crash or, potentially, execute code running the library on Linux. How do I patch and protect my server or workstation against the glibc getaddrinfo on Linux operating system?
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Linux Check Disk Space Command

I recently switched from a Windows server to a Linux server operating system. I am using Ubuntu LTS server. How do I find out disk space utilization information using command line option?
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How To Patch and Protect Linux Kernel Zero Day Vulnerability CVE-2016-0728 [ 19/Jan/2016 ]

A very serious security problem has been found in the Linux kernel. A 0-day local privilege escalation vulnerability has existed since 2012. This bug affects millions of Android or Linux applications to escalate privileges. Any server or desktop (32 or 64 bit) with Linux Kernel version 3.8+ is vulnerable. How do I fix this problem?
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