The Problem A non-privileged user cannot edit their crontab file using the command “crontab -e” $ crontab -e no crontab for oracle – using an empty one /tmp/crontab.Lm34gsJV: Permission denied $ The Solution This can happen mainly due to wrong permission on /tmp directory. When a user tries to edit the crontab using ‘crontab -e’ […]
Archives for June 2020
showmount Command Examples in Linux
showmount command shows information about an NFS server. This information is maintained by the mountd server on the host. The default value for the host is the value returned by the hostname. With no options, show the clients that have mounted directories from the host. showmount is usually found in /usr/sbin, which is not in […]
How to Enable Debug Mode for Chronyd Service in CentOS/RHEL 8
What is Chronyd Service In CentOS/RHEL 7 and 8, the operating system’s time is set on every boot based on the hardware clock, which is a small-battery driven clock located on the motherboard of your computer. Often, this clock is too inaccurate or has not been set right, therefore it’s better to get your system […]
How to Recover from a Corrupted or empty /etc/mtab file in CentOS/RHEL 7
Sometimes you may get an error while running the df command saying that tat the /etc/mtab file is either corrupt or empty(removed). It may be a case that someone accidentally edited the /etc/mtab file and has incorrect data. Well, this post will help you restore your correct mtab file. What is the use of /etc/mtab […]
File Access Commands in Linux – find, sort, head, tail
The following file access commands are UNIX commands, not specific shell commands. Command Remakr find Finds the location of a file sort Reads a file and sort the output hear or tail Looks at just the start or end of a file The find Command The find command allows you to search for files and […]
Status Commands in Linux – date, ps, who, uptime, finger, rup, ruser
The status commands are UNIX commands, not specific shell commands. Command Purpose date Displays the current (system) date and time ps Displays information about system processes who Display which users are logged in to the system rusers Displays the users on local area network (LAN) systems finger Displays information about logged-in users uptime Displays how […]
CentOS/RHEL : Unmounting a Windows Share Fails – “device is busy”
The Problem Unable to unmount a Windows share mount point using umount command. This Windows share is not being used by any processes recently. When executing umount command, the following error is seen; umount: /data01: device is busy. (In some cases useful info about processes that use the device is found by lsof(8) or fuser(1)) […]