Question

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In Linux:

• Identify three commands that use SUID mode. Discuss why this is so?
• Identify the commands that are generally causing the highest load on your system and discuss your perspectives on why they cause such a load. Discuss your perspectives on the considerations system administration must give while using these commands.

Answer 1

Three commands that use SUID mode are (i) passwd, (ii) ping, (iii) crontab or at.

SUID: SUID stands for Set owner User IDentity. Using this mode the users will get file owner's permission and UID when executing the program or any task.

• "passwd" command is used to change the password which is owned by owner or root, the user has to take permission from the owner. For this purpose the user will use SUID mode to get permission.
• "ping" command is used to open socket files and ports in order to send and receive IP packets, the user uses SUID mode to take permission from the owner.
• "crontab" or "at" command is used to edit some of the files which are owned by the owner, the user has to take permission. For this purpose user uses SUID mode.

The list of commands that are generally causing the highest load on your system:

• vmstat
• uptime
• pmstat
• iotop
• iostat

By using all these commands we can get logged into non-responsive system and we may face hardware errors. Some of them will update and print statistics for every interval of seconds while dealing with I/O activities. So it will be high load to the system. Sometimes though the system uses older kernel, we may run some commands which are not capable for those systems. This will also cause high load to the system.

It is better to use SUID mode to get rid of unauthorized access of any user. SUID mode will ask for the authorization of user. So user has to take permission from the owner. By using SUID mode we can achieve security and proper execution.

The commands which are causing the highest load will provide detailed information from time to time. They even provide the statistics of the execution. Of course this leads to high load but better to increase the time of interval.