Showing posts with label Linux System Management. Show all posts
Showing posts with label Linux System Management. Show all posts

Wednesday, April 1, 2015

Linux System Management

Environment
env
Show all environment variables.
export
Set the value of a variable so it is visible to all subprocesses that belong to the current shell.
printenv
Print all or part of environment.
reset
Restores runtime parameters for session to default values.
set
Shows how the environment is set up. This is a builtin bash command.
Library management
ldconfig
Updates the necessary links for the run time link bindings.
ldd
Tells what libraries a given program needs to run.
ltrace
A library call tracer.
trace
Same as ltrace.
Module and kernel management
depmod
Handle loadable modules automatically. Creates a makefile-like dependency file.
dmesg
Print or control the kernel ring buffer. This shows the last kernel startup messages.
genksyms
Generate symbol version information.
insmod
Install loadable kernel module.
lsmod
List currently installed kernel modules.
modprobe
Used to load a set of modules that are marked with a specified tag.
rmmod
Unload loadable modules.
Runtime level management
exit
Terminates the shell.
halt
Stop the system.
init
Process control initialization.
initscript
Script that executes inittab commands.
logout
Log the user off the system.
poweroff
Brings the system down.
reboot
Reboot the system.
runlevel
List the current and previous runlevel.
setsid
Run a program in a new session.
shutdown
If your system has many users, use the command "shutdown -h +time message", where time is the time in minutes until the system is halted, and message is a short explanation of why the system is shutting down.
# shutdown -h +10 'We will install a new disk. System should be back on-line in three hours.'
telinit
By requesting run level 1 a system can be taken to single user mode.
System Configuration tools
ctrlaltdel
Set the function of the ctrl alt del combination.
isapnp
Configure ISA plug and play devices.
kbdconf
A Redhat Linux tool which configures the /etc/sysconfig/keyboard file which specifies the location of the keyboard map file. This is a GUI based tool.
kbdrate
Set the keyboard repeat rate and delay time.
kernelcfg
A Redhat GUI kernel configuration tool, Start X, then run it from a console session.
linuxconf
Redhat's GUI linux system configuration tool.
lspci
List all pci devices.
mesg
Control write access to your terminal.
mouseconfig
A Redhat Linux tool used to configure the /etc/sysconfig.mouse file. This is a GUI tool.
ndc
Script file used to restart, stop, start the DNS server.
Printtool
Redhat's GUI printer configuration tool.
quota
Display disk usage and limits.
quotacheck
Scan a filesystem for disk usages.
quotaoff
Turn file system quotas off.
quotaon
Turn file system quotas on.
samba
Script file used to stop, start, restart samba services when not run using inetd.
setpci
Configure pci devices.
setserial
Set/get serial port information.
setterm
Set terminal attributes.
setup
Set up devices and file systems.
stty
Used to configure and print the console devices.
swapon
Enable devices and files for paging and swapping.
swapoff
Disable devices and files for paging and swapping.
timeconfig
A Redhat Linux tool used to configure the /etc/sysconfig/clock file. This is a GUI tool used to set timezone and whether or not the clock is set to GMT time.
tset
Used to initialize terminals.
System Information                 
arch
Print machine architecture.
df
Shows disk free space.
du
Shows disk usage.
free
Display used and free memory on the system.
ipcrm
Provide information on ipc facilities.
ipcs
Same as ipcrm.
lsdev
Display information about installed hardware via files in the /proc directory.
lsof
List open files.
lspci
List PCI devices .
pnpdump
Lists ISA plug and play devices resource information.
procinfo
Display system status gathered from proc.
pstree
Display a tree of processes.
runlevel
Find the current and previous system runlevel.
strace
Trace ssytem calls and signals for a binary program.
stty
Change and print terminal line settings.
tload
Prints a graphic representation of the system load average.
tty
Print the filename of the terminal connected to standard input.
uname
Print system information, Prints Linux.
vmstat
Report virtual memory statistics.
xcpustate
Displays CPU states (idle, nice, system, kernel) statistics. Runs in X?
System Logging
klogd
Kernel log daemon which intercepts and logs Linux kernel messages.
logger
Make entries in the system log.
syslogd
Linux system logging utilities.
sysklogd
Linux system logging utilities.
System Security

System time
cal
Calendar.
clock
Used to change or get current time. The command "clock -–w" sets the hardware clock.
date
Print or set the system date and time.
hwclock
Set or read the hardware CMOS clock.
timed
Time server daemon to synchronize the host's time with other machines, normally invoked at boot time from the rc(8) file.
timedc
Timed control program.
tzset
Used to change the users private time zone by setting the TZ environment variable.
uptime
Reports how long the system has been running.
zdump
Prints the current time in each zonename named on the command line.
zic
Reads text from files named on the command line and creates time conversion files.
X Management and programs
SuperProbe
Probe video hardware.
Xconfigurator
The Redhat tool used during system setup to configure X.
xconsole
Displays messages usually sent to /dev/console.
xf86config
Older version of XF86Setup.
XF86Setup
A newer X configuration program with a GUI interface which modifies the "/etc/X11/XF86Config" configuration file.
xvidtune
This program will test video modes on the fly without modification to your X configuration. Read the usr/X11R6/lib/X11/doc/VideoModes.doc file before running this program.