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  1. Introduction

    Files and File Structure

  2. File Structure
  3. Configuration Files
  4. File Formats


  5. Filesystem Management
  6. File Management and Viewing
  7. Help, Job and Process Management
  8. Network Management
  9. System Management
  10. User Management
  11. Printing and Programming
  12. Document Preparation
  13. Miscellaneous
  14. Credits

Linux System Management


envShow all environment variables.
exportSet the value of a variable so it is visible to all subprocesses that belong to the current shell.
printenvPrint all or part of environment.
resetRestores runtime parameters for session to default values.
setShows how the environment is set up. This is a builtin bash command.

Library management

ldconfigUpdates the necessary links for the run time link bindings.
lddTells what libraries a given program needs to run.
ltraceA library call tracer.
traceSame as ltrace.

Module and kernel management

depmodHandle loadable modules automatically. Creates a makefile-like dependency file.
dmesgPrint or control the kernel ring buffer. This shows the last kernel startup messages.
genksymsGenerate symbol version information.
insmodInstall loadable kernel module.
lsmodList currently installed kernel modules.
modprobeUsed to load a set of modules that are marked with a specified tag.
rmmodUnload loadable modules.

Runtime level management

exitTerminates the shell.
haltStop the system.
initProcess control initialization.
initscriptScript that executes inittab commands.
logoutLog the user off the system.
poweroffBrings the system down.
rebootReboot the system.
runlevelList the current and previous runlevel.
setsidRun a program in a new session.
shutdownIf 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.'
telinitBy requesting run level 1 a system can be taken to single user mode.

System Configuration tools

ctrlaltdelSet the function of the ctrl alt del combination.
isapnpConfigure 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.
kbdrateSet the keyboard repeat rate and delay time.
kernelcfgA Redhat GUI kernel configuration tool, Start X, then run it from a console session.
linuxconfRedhat's GUI linux system configuration tool.
lspciList all pci devices.
mesgControl write access to your terminal.
mouseconfigA Redhat Linux tool used to configure the /etc/sysconfig.mouse file. This is a GUI tool.
ndcScript file used to restart, stop, start the DNS server.
PrinttoolRedhat's GUI printer configuration tool.
quotaDisplay disk usage and limits.
quotacheckScan a filesystem for disk usages.
quotaoffTurn file system quotas off.
quotaonTurn file system quotas on.
sambaScript file used to stop, start, restart samba services when not run using inetd.
setpciConfigure pci devices.
setserialSet/get serial port information.
settermSet terminal attributes.
setupSet up devices and file systems.
sttyUsed to configure and print the console devices.
swaponEnable devices and files for paging and swapping.
swapoffDisable devices and files for paging and swapping.
timeconfigA 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.
tsetUsed to initialize terminals.

System Information

archPrint machine architecture.
df Shows disk free space.
duShows disk usage.
freeDisplay used and free memory on the system.
ipcrmProvide information on ipc facilities.
ipcsSame as ipcrm.
lsdevDisplay information about installed hardware via files in the /proc directory.
lsofList open files.
lspciList PCI devices .
pnpdumpLists ISA plug and play devices resource information.
procinfoDisplay system status gathered from proc.
pstreeDisplay a tree of processes.
runlevelFind the current and previous system runlevel.
straceTrace ssytem calls and signals for a binary program.
sttyChange and print terminal line settings.
tloadPrints a graphic representation of the system load average.
ttyPrint the filename of the terminal connected to standard input.
unamePrint system information, Prints Linux.
vmstatReport virtual memory statistics.
xcpustateDisplays CPU states (idle, nice, system, kernel) statistics. Runs in X?

System Logging

klogdKernel log daemon which intercepts and logs Linux kernel messages.
loggerMake entries in the system log.
syslogdLinux system logging utilities.
sysklogdLinux system logging utilities.

System Security

System time

clockUsed to change or get current time. The command "clock -w" sets the hardware clock.
datePrint or set the system date and time.
hwclockSet or read the hardware CMOS clock.
timedTime server daemon to synchronize the host's time with other machines, normally invoked at boot time from the rc(8) file.
timedcTimed control program.
tzsetUsed to change the users private time zone by setting the TZ environment variable.
uptimeReports how long the system has been running.
zdumpPrints the current time in each zonename named on the command line.
zicReads text from files named on the command line and creates time conversion files.

X Management and programs

SuperProbeProbe video hardware.
XconfiguratorThe Redhat tool used during system setup to configure X.
xconsoleDisplays messages usually sent to /dev/console.
xf86configOlder version of XF86Setup.
XF86SetupA newer X configuration program with a GUI interface which modifies the "/etc/X11/XF86Config" configuration file.
xvidtuneThis 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.