Process management

The following are common commands and utilities for process management in Linux.

1 Process management

Command	Function
at -d job ID	Cancels scheduled job according to job ID; equivalent to atrm
at -l cmd	Lists scheduled jobs; equivalent to atq
at time cmd	Runs a command at a specified time
bg	Moves a running process to the background.
bpytop	A new top alternative (requires installation)
cmd &	Start a process and send it to the background
crontab -e	Edit crontable
crontab -l	List scheduled tasks
crontab -r	Remove crontable
df	Display information on system disks, e.g., free and used storage
dmesg -k	Outputs system messages (helpful for troubleshooting)
dmesg -k	Display system messages
fg	Brings the most recent background job to the foreground
fg PID	Brings a job to the foreground
free	Display information about RAM and swap, free and used memory.
fuser	Show which processes are using a particular file, device, or system resource
fuser -m /dev/sda1	Show which processes are using a particular device
history	Print a history list of all commands issued within a particular shell
htop	Display all running processes in real time (alternative to top)
jobs	List all jobs presently running
journalctl	System logs
journalctl _UID=1000	View log entries for a specific user by user ID
journalctl --since "YYYY-MM-DD HH:MM" --until "YYYY-MM-DD HH:MM"	Filter and display log entries for a certain time period
journalctl -f	Follow system logs in real time
journalctl -u httpd -n 3	View 3 log entries for httpd
journalctl -u sshd	View log entries for only SSH
kill	Terminate a running process.
kill -1 OR -15	Soft kill a process
kill -2	Interrupt process; equivalent to CTL-c
kill -9	Kill a process forcefully and immediately
kill -l	List kill signal names
kill PID	Kills a running process of a specified process ID.
killall procname	Kill all processes of the specified name
lsof	List all files opened by running processes
lsof	Display currently open files
nice	Grant execution rights to a process with an assigned priority.
nohup	Allow a process to continue after logging out
pidof	Shows the process ID of a specified process.
pidof procname	Find the PID of a process
ps	Display currently running processes
ps -ef	Display all active processes
grep procname	Display information on a specific process
ps aux	Display information on running processes in BSD format
ps PID	Display the status of a running processes by its process ID
pstree	Display processes in the tree-like diagram
renice	Change or alter the execution priority of an already running system process
renice -5 PID	Adjust priority level of a running process by process ID
script	Record terminal session activity and create output for the session in a file
sensors	Outputs the system's CPU temperature
stop\|restart	Used for managing system services through an executable sysV init script. You can start, stop, or restart the specified system service.
systemctl status service	Change the status of a service managed by systemctl
time	Print time taken for a command to finish running
top	Manage and display all processes in real time
whereis	Show locations of binary, source and manual pages for a command
which program	Show the commands associated with an application

2 Rsync

Command	Function
rsycn -av –exclude ‘*.txt’ /src_dir/ /dest_dir	Archive but exclude a specific file type
rsync -av --max-size=1000m src_dir/ dest_dir/	Archive but exclude files over a certain size
rsync -av –exclude ‘dir’ /src_dir/ /dest_dir	Archive but exclude a specific directory from the source location
rsync -av /src_dir/ dest_dir	Archival backup (recursively, preserving links and file attributes; v=verbose)
rsync -avR /a/b/xyz.c remote:/tmp/	Archive a file on a remote machine, preserving the relative path (e.g., creating /tmp/a/b/xyz.c)
rsync -avz /src_dir/ /dest_dir	Archive as a compressed file
rsync /source_dir/ /desitnation_dir OR source_dir/ destination_dir/	Backup a directory to a different location