HCL Group Linux Administrator Interview Questions and Answers

To schedule a cron job, use the crontab command to edit the cron table file.

• Use the crontab -e command to open the cron table file for editing

• Add a new line to the file with the schedule timing and the command to be executed

• Save and exit the file to schedule the cron job

Sticky bit is a permission in Unix/Linux that allows only the owner of a file to delete or rename it.

• Sticky bit is represented by a 't' in the permissions of a file or directory.

• When the sticky bit is set on a directory, only the owner of a file within that directory can delete or rename the file.

• Commonly used on directories like /tmp to prevent users from deleting each other's files.

• Example: chmod +t directory_name

top and ps are commands used in Linux to display information about running processes and system resource usage.

• top command displays real-time information about running processes, CPU usage, and memory usage

• ps command displays a snapshot of the current processes running on the system

• Both commands can be used to monitor system performance and troubleshoot issues

Linux is an open-source operating system based on Unix. Its components include kernel, shell, GUI, utilities, and applications.

• Kernel: manages hardware resources and provides services to other system components

• Shell: provides a command-line interface for users to interact with the system

• GUI: provides a graphical interface for users to interact with the system

• Utilities: perform various system tasks such as file manageme...read more

Links are pointers to files or directories. Linux permissions control access to files and directories.

• Links can be hard links or symbolic links

• Hard links point directly to the file's inode

• Symbolic links point to the file's path

• Linux permissions are divided into three categories: owner, group, and others

• Each category has three types of permissions: read, write, and execute

• Permissions can be set using chmod command

Rollback patching is a process of reverting a patch or update to a previous version.

• Rollback patching is useful when a patch or update causes issues or conflicts with the system.

• It involves undoing the changes made by the patch or update and restoring the system to its previous state.

• Rollback patching can be done manually or automatically depending on the system and the patching process.

• Examples of rollback patching to...read more

To check logs at a particular time and send a report to the client, use the 'grep' command and a cron job.

• Use the 'grep' command to search for logs at a specific time.

• Create a cron job to run the 'grep' command at the desired time.

• Use a script to format the log data and send it to the client.

• Consider using a tool like Logwatch or Logrotate for automated log management.

To create a repository, you need to choose a package manager and create a configuration file.

• Choose a package manager like YUM or APT

• Create a configuration file with repository details

• Add packages to the repository

• Sign the repository to ensure package integrity

• Publish the repository for others to use