Process Management

Question 1

What command is used to send a signal to a process?

Answer 1

■ kill

■ usage: kill [-signal] PID

Question 2

What command is used to send a signal to one or more processes matching selection criteria?

Answer 2

■ killall

■ usage: killall [-signal] command_pattern

Question 3

What advanced command can be used to send a signal to one or more processes based on command, UID, GID, Parent or terminal?

Answer 3

■ pkill
■ usage: pkill command_pattern
■ usage: pkill -signal command_pattern
■ usage: pkill -G GID command_pattern
■ usage: pkill -P PPID command_pattern
■ usage: pkill -t terminal_name -U UID command_pattern

Question 4

What command views users currently logged into the system and their cumulative activities?

Answer 4

■ ‘w’

■ w [options] user

Question 5

What command is used to look up processes to list IDs matching a selection criteria?

Answer 5

■ pgrep
■ usage: pgrep [options] pattern
■ usage: pgrep -l -u

Question 6

What command can be used to view the process tree for the system or a single user?

Answer 6

■ pstree

■ usage: pstree [options]

Question 7

What resources should be checked when experiencing high load averages with minimal CPU activity?

Answer 7

■ Disk activity

■ Network activity

Question 8

What do the value of the load average represent?

Answer 8

■ The weighted values over the last 1, 5, and 15 minutes.

Question 9

What utilities display load average values?

Answer 9

■ top
■ uptime
■ w
■ gnome-system-monitor

Question 10

What so the displayed load average values mean?

Answer 10

■ Below 1 indicates satisfactory resource utilization and minimal wait times.
■ Above 1 indicates resource saturation and some amount of service waiting times.

Question 11

What are the levels nice provides for program execution priority?

Answer 11

■ -20 to -1 (most favorable to process)

■ 0 to 19 (least favorable to process)

Question 12

What does the ‘nice’ command do?

Answer 12

■ Runs a program with a modified scheduling priority.

Question 13

What does the ‘renice’ command do?

Answer 13

■ Alters the priority of running processes.

■ Regular users can only raise the nice level of their processes. Only root can lower the nice level.

Question 14

What options allow for sorting and output formatting when using ‘ps’?

Answer 14

■ -o (followed by column names like: pcpu,pid,comm,user)

■ –sort (like –sort=pcpu,user)

Question 15

What does $(pgrep [commandname] ) do?

Answer 15

■ Returns all instances of the command and their PIDs.