Note: the list of commands is based on the topic order in its first appearance at the learning material provided by LPI (based on the exams objectives). Although inside each topic the commands were ordered alphabetically. The sources of each description are their respective man pages and usage/help shorts from command.
- Topic 101: System Architecture
- Topic 102: Linux Installation and Package Management
- Topic 103: GNU and Unix Commands
- Topic 104: Devices, Linux Filesystems, Filesystem Hierarchy Standard
- Topic 105: Shells and Shell Scripting
- Topic 106: User Interfaces and Desktops
- Topic 107: Administrative Tasks
- Topic 108: Essential System Services
- Topic 109: Networking Fundamentals
- Topic 110: Security
It is used to examine or control the kernel ring buffer. The default action is to display all messages from the kernel ring buffer.
$ dmesg --help
Usage:
dmesg [options]
Display or control the kernel ring buffer.
Options:
-C, --clear clear the kernel ring buffer
-c, --read-clear read and clear all messages
-D, --console-off disable printing messages to console
-E, --console-on enable printing messages to console
-F, --file <file> use the file instead of the kernel log buffer
-f, --facility <list> restrict output to defined facilities
-H, --human human readable output
-k, --kernel display kernel messages
-L, --color[=<when>] colorize messages (auto, always or never)
colors are enabled by default
-l, --level <list> restrict output to defined levels
-n, --console-level <level> set level of messages printed to console
-P, --nopager do not pipe output into a pager
-r, --raw print the raw message buffer
-S, --syslog force to use syslog(2) rather than /dev/kmsg
-s, --buffer-size <size> buffer size to query the kernel ring buffer
-u, --userspace display userspace messages
-w, --follow wait for new messages
-x, --decode decode facility and level to readable string
-d, --show-delta show time delta between printed messages
-e, --reltime show local time and time delta in readable format
-T, --ctime show human-readable timestamp (may be inaccurate!)
-t, --notime don't show any timestamp with messages
--time-format <format> show timestamp using the given format:
[delta|reltime|ctime|notime|iso]
Suspending/resume will make ctime and iso timestamps inaccurate.
-h, --help display this help
-V, --version display version
Supported log facilities:
kern - kernel messages
user - random user-level messages
mail - mail system
daemon - system daemons
auth - security/authorization messages
syslog - messages generated internally by syslogd
lpr - line printer subsystem
news - network news subsystem
Supported log levels (priorities):
emerg - system is unusable
alert - action must be taken immediately
crit - critical conditions
err - error conditions
warn - warning conditions
notice - normal but significant condition
info - informational
debug - debug-level messages
For more details see dmesg(1).
Systemd is a system and service manager for Linux operating systems. When run as first process on boot (as PID 1), it acts as init system that brings up and maintains userspace services.
$ init --help
init [OPTIONS...] {COMMAND}
Send control commands to the init daemon.
--help Show this help
--no-wall Don't send wall message before halt/power-off/reboot
Commands:
0 Power-off the machine
6 Reboot the machine
2, 3, 4, 5 Start runlevelX.target unit
1, s, S Enter rescue mode
q, Q Reload init daemon configuration
u, U Reexecute init daemon
It may be used to query the contents of the systemd journal as written by systemd-journald.service.
$ journalctl --help
journalctl [OPTIONS...] [MATCHES...]
Query the journal.
Options:
--system Show the system journal
--user Show the user journal for the current user
-M --machine=CONTAINER Operate on local container
-S --since=DATE Show entries not older than the specified date
-U --until=DATE Show entries not newer than the specified date
-c --cursor=CURSOR Show entries starting at the specified cursor
--after-cursor=CURSOR Show entries after the specified cursor
--show-cursor Print the cursor after all the entries
-b --boot[=ID] Show current boot or the specified boot
--list-boots Show terse information about recorded boots
-k --dmesg Show kernel message log from the current boot
-u --unit=UNIT Show logs from the specified unit
--user-unit=UNIT Show logs from the specified user unit
-t --identifier=STRING Show entries with the specified syslog identifier
-p --priority=RANGE Show entries with the specified priority
-g --grep=PATTERN Show entries with MESSSAGE matching PATTERN
--case-sensitive[=BOOL] Force case sensitive or insenstive matching
-e --pager-end Immediately jump to the end in the pager
-f --follow Follow the journal
-n --lines[=INTEGER] Number of journal entries to show
--no-tail Show all lines, even in follow mode
-r --reverse Show the newest entries first
-o --output=STRING Change journal output mode (short, short-precise,
short-iso, short-iso-precise, short-full,
short-monotonic, short-unix, verbose, export,
json, json-pretty, json-sse, cat)
--output-fields=LIST Select fields to print in verbose/export/json modes
--utc Express time in Coordinated Universal Time (UTC)
-x --catalog Add message explanations where available
--no-full Ellipsize fields
-a --all Show all fields, including long and unprintable
-q --quiet Do not show info messages and privilege warning
--no-pager Do not pipe output into a pager
--no-hostname Suppress output of hostname field
-m --merge Show entries from all available journals
-D --directory=PATH Show journal files from directory
--file=PATH Show journal file
--root=ROOT Operate on files below a root directory
--interval=TIME Time interval for changing the FSS sealing key
--verify-key=KEY Specify FSS verification key
--force Override of the FSS key pair with --setup-keys
Commands:
-h --help Show this help text
--version Show package version
-N --fields List all field names currently used
-F --field=FIELD List all values that a specified field takes
--disk-usage Show total disk usage of all journal files
--vacuum-size=BYTES Reduce disk usage below specified size
--vacuum-files=INT Leave only the specified number of journal files
--vacuum-time=TIME Remove journal files older than specified time
--verify Verify journal file consistency
--sync Synchronize unwritten journal messages to disk
--flush Flush all journal data from /run into /var
--rotate Request immediate rotation of the journal files
--header Show journal header information
--list-catalog Show all message IDs in the catalog
--dump-catalog Show entries in the message catalog
--update-catalog Update the message catalog database
--new-id128 Generate a new 128-bit ID
--setup-keys Generate a new FSS key pair
Utility for displaying information about PCI buses in the system and devices connected to them. By default, it shows a brief list of devices.
$ lspci -
Usage: lspci [<switches>]
Basic display modes:
-mm Produce machine-readable output (single -m for an obsolete format)
-t Show bus tree
Display options:
-v Be verbose (-vv for very verbose)
-k Show kernel drivers handling each device
-x Show hex-dump of the standard part of the config space
-xxx Show hex-dump of the whole config space (dangerous; root only)
-xxxx Show hex-dump of the 4096-byte extended config space (root only)
-b Bus-centric view (addresses and IRQ's as seen by the bus)
-D Always show domain numbers
Resolving of device ID's to names:
-n Show numeric ID's
-nn Show both textual and numeric ID's (names & numbers)
-q Query the PCI ID database for unknown ID's via DNS
-qq As above, but re-query locally cached entries
-Q Query the PCI ID database for all ID's via DNS
Selection of devices:
-s [[[[<domain>]:]<bus>]:][<slot>][.[<func>]] Show only devices in selected slots
-d [<vendor>]:[<device>][:<class>] Show only devices with specified ID's
Other options:
-i <file> Use specified ID database instead of /usr/share/misc/pci.ids.gz
-p <file> Look up kernel modules in a given file instead of default modules.pcimap
-M Enable `bus mapping' mode (dangerous; root only)
PCI access options:
-A <method> Use the specified PCI access method (see `-A help' for a list)
-O <par>=<val> Set PCI access parameter (see `-O help' for a list)
-G Enable PCI access debugging
-H <mode> Use direct hardware access (<mode> = 1 or 2)
-F <file> Read PCI configuration dump from a given file
Program which nicely formats the contents of the /proc/modules, showing what kernel modules are currently loaded.
$ lsmod --help
Usage: lsmod
Utility for displaying information about USB buses in the system and the devices connected to them.
$ lsusb --help
Usage: lsusb [options]...
List USB devices
-v, --verbose
Increase verbosity (show descriptors)
-s [[bus]:][devnum]
Show only devices with specified device and/or
bus numbers (in decimal)
-d vendor:[product]
Show only devices with the specified vendor and
product ID numbers (in hexadecimal)
-D device
Selects which device lsusb will examine
-t, --tree
Dump the physical USB device hierarchy as a tree
-V, --version
Show version of program
-h, --help
Show usage and help
Extracts information from the Linux Kernel modules given on the command line.
$ modinfo --help
Usage:
modinfo [options] filename [args]
Options:
-a, --author Print only 'author'
-d, --description Print only 'description'
-l, --license Print only 'license'
-p, --parameters Print only 'parm'
-n, --filename Print only 'filename'
-0, --null Use \0 instead of \n
-F, --field=FIELD Print only provided FIELD
-k, --set-version=VERSION Use VERSION instead of `uname -r`
-b, --basedir=DIR Use DIR as filesystem root for /lib/modules
-V, --version Show version
-h, --help Show this help
Adds or remove modules from the Linux Kernel.
$ modprobe --help
Usage:
modprobe [options] [-i] [-b] modulename
modprobe [options] -a [-i] [-b] modulename [modulename...]
modprobe [options] -r [-i] modulename
modprobe [options] -r -a [-i] modulename [modulename...]
modprobe [options] -c
modprobe [options] --dump-modversions filename
Management Options:
-a, --all Consider every non-argument to
be a module name to be inserted
or removed (-r)
-r, --remove Remove modules instead of inserting
--remove-dependencies Also remove modules depending on it
-R, --resolve-alias Only lookup and print alias and exit
--first-time Fail if module already inserted or removed
-i, --ignore-install Ignore install commands
-i, --ignore-remove Ignore remove commands
-b, --use-blacklist Apply blacklist to resolved alias.
-f, --force Force module insertion or removal.
implies --force-modversions and
--force-vermagic
--force-modversion Ignore module's version
--force-vermagic Ignore module's version magic
Query Options:
-D, --show-depends Only print module dependencies and exit
-c, --showconfig Print out known configuration and exit
-c, --show-config Same as --showconfig
--show-modversions Dump module symbol version and exit
--dump-modversions Same as --show-modversions
General Options:
-n, --dry-run Do not execute operations, just print out
-n, --show Same as --dry-run
-C, --config=FILE Use FILE instead of default search paths
-d, --dirname=DIR Use DIR as filesystem root for /lib/modules
-S, --set-version=VERSION Use VERSION instead of `uname -r`
-s, --syslog print to syslog, not stderr
-q, --quiet disable messages
-v, --verbose enables more messages
-V, --version show version
-h, --help show this help
Prints the previous and current SysV runlevel if they are known. The two runlevel characters are separated by a single space character. If a runlevel cannot be determined, N is printed instead. If neither can be determined, the word "unknown" is printed.
$ runlevel --help
runlevel [OPTIONS...]
Prints the previous and current runlevel of the init system.
--help Show this help
It may be used to halt, power-off or reboot the machine.
$ shutdown --help
shutdown [OPTIONS...] [TIME] [WALL...]
Shut down the system.
--help Show this help
-H --halt Halt the machine
-P --poweroff Power-off the machine
-r --reboot Reboot the machine
-h Equivalent to --poweroff, overridden by --halt
-k Don't halt/power-off/reboot, just send warnings
--no-wall Don't send wall message before halt/power-off/reboot
-c Cancel a pending shutdown
It may be used to introspect and control the state of the "systemd" system and service manager.
$ systemctl --help
systemctl [OPTIONS...] {COMMAND} ...
Query or send control commands to the systemd manager.
-h --help Show this help
--version Show package version
--system Connect to system manager
--user Connect to user service manager
-H --host=[USER@]HOST
Operate on remote host
-M --machine=CONTAINER
Operate on local container
-t --type=TYPE List units of a particular type
--state=STATE List units with particular LOAD or SUB or ACTIVE state
-p --property=NAME Show only properties by this name
-a --all Show all properties/all units currently in memory,
including dead/empty ones. To list all units installed on
the system, use the 'list-unit-files' command instead.
--failed Same as --state=failed
-l --full Don't ellipsize unit names on output
-r --recursive Show unit list of host and local containers
--reverse Show reverse dependencies with 'list-dependencies'
--job-mode=MODE Specify how to deal with already queued jobs, when
queueing a new job
--show-types When showing sockets, explicitly show their type
--value When showing properties, only print the value
-i --ignore-inhibitors
When shutting down or sleeping, ignore inhibitors
--kill-who=WHO Who to send signal to
-s --signal=SIGNAL Which signal to send
--now Start or stop unit in addition to enabling or disabling it
--dry-run Only print what would be done
-q --quiet Suppress output
--wait For (re)start, wait until service stopped again
--no-block Do not wait until operation finished
--no-wall Don't send wall message before halt/power-off/reboot
--no-reload Don't reload daemon after en-/dis-abling unit files
--no-legend Do not print a legend (column headers and hints)
--no-pager Do not pipe output into a pager
--no-ask-password
Do not ask for system passwords
--global Enable/disable/mask unit files globally
--runtime Enable/disable/mask unit files temporarily until next
reboot
-f --force When enabling unit files, override existing symlinks
When shutting down, execute action immediately
--preset-mode= Apply only enable, only disable, or all presets
--root=PATH Enable/disable/mask unit files in the specified root
directory
-n --lines=INTEGER Number of journal entries to show
-o --output=STRING Change journal output mode (short, short-precise,
short-iso, short-iso-precise, short-full,
short-monotonic, short-unix,
verbose, export, json, json-pretty, json-sse, cat)
--firmware-setup Tell the firmware to show the setup menu on next boot
--plain Print unit dependencies as a list instead of a tree
Unit Commands:
list-units [PATTERN...] List units currently in memory
list-sockets [PATTERN...] List socket units currently in memory, ordered
by address
list-timers [PATTERN...] List timer units currently in memory, ordered
by next elapse
start NAME... Start (activate) one or more units
stop NAME... Stop (deactivate) one or more units
reload NAME... Reload one or more units
restart NAME... Start or restart one or more units
try-restart NAME... Restart one or more units if active
reload-or-restart NAME... Reload one or more units if possible,
otherwise start or restart
try-reload-or-restart NAME... If active, reload one or more units,
if supported, otherwise restart
isolate NAME Start one unit and stop all others
kill NAME... Send signal to processes of a unit
is-active PATTERN... Check whether units are active
is-failed PATTERN... Check whether units are failed
status [PATTERN...|PID...] Show runtime status of one or more units
show [PATTERN...|JOB...] Show properties of one or more
units/jobs or the manager
cat PATTERN... Show files and drop-ins of one or more units
set-property NAME ASSIGNMENT... Sets one or more properties of a unit
help PATTERN...|PID... Show manual for one or more units
reset-failed [PATTERN...] Reset failed state for all, one, or more
units
list-dependencies [NAME] Recursively show units which are required
or wanted by this unit or by which this
unit is required or wanted
Unit File Commands:
list-unit-files [PATTERN...] List installed unit files
enable [NAME...|PATH...] Enable one or more unit files
disable NAME... Disable one or more unit files
reenable NAME... Reenable one or more unit files
preset NAME... Enable/disable one or more unit files
based on preset configuration
preset-all Enable/disable all unit files based on
preset configuration
is-enabled NAME... Check whether unit files are enabled
mask NAME... Mask one or more units
unmask NAME... Unmask one or more units
link PATH... Link one or more units files into
the search path
revert NAME... Revert one or more unit files to vendor
version
add-wants TARGET NAME... Add 'Wants' dependency for the target
on specified one or more units
add-requires TARGET NAME... Add 'Requires' dependency for the target
on specified one or more units
edit NAME... Edit one or more unit files
get-default Get the name of the default target
set-default NAME Set the default target
Machine Commands:
list-machines [PATTERN...] List local containers and host
Job Commands:
list-jobs [PATTERN...] List jobs
cancel [JOB...] Cancel all, one, or more jobs
Environment Commands:
show-environment Dump environment
set-environment NAME=VALUE... Set one or more environment variables
unset-environment NAME... Unset one or more environment variables
import-environment [NAME...] Import all or some environment variables
Manager Lifecycle Commands:
daemon-reload Reload systemd manager configuration
daemon-reexec Reexecute systemd manager
System Commands:
is-system-running Check whether system is fully running
default Enter system default mode
rescue Enter system rescue mode
emergency Enter system emergency mode
halt Shut down and halt the system
poweroff Shut down and power-off the system
reboot [ARG] Shut down and reboot the system
kexec Shut down and reboot the system with kexec
exit [EXIT_CODE] Request user instance or container exit
switch-root ROOT [INIT] Change to a different root file system
suspend Suspend the system
hibernate Hibernate the system
hybrid-sleep Hibernate and suspend the system
suspend-then-hibernate Suspend the system, wake after a period of
time and put it into hibernate
It may be used to change the SysV system runlevel.
$ telinit --help
telinit [OPTIONS...] {COMMAND}
Send control commands to the init daemon.
--help Show this help
--no-wall Don't send wall message before halt/power-off/reboot
Commands:
0 Power-off the machine
6 Reboot the machine
2, 3, 4, 5 Start runlevelX.target unit
1, s, S Enter rescue mode
q, Q Reload init daemon configuration
u, U Reexecute init daemon
It installs GRUB on your drive.
$ grub-install --help
Usage: grub-install [OPTION...] [OPTION] [INSTALL_DEVICE]
Install GRUB on your drive.
--compress=no|xz|gz|lzo compress GRUB files [optional]
-d, --directory=DIR use images and modules under DIR
[default=/usr/lib/grub/<platform>]
--fonts=FONTS install FONTS [default=unicode]
--install-modules=MODULES install only MODULES and their dependencies
[default=all]
-k, --pubkey=FILE embed FILE as public key for signature checking
--locale-directory=DIR use translations under DIR
[default=/usr/share/locale]
--locales=LOCALES install only LOCALES [default=all]
--modules=MODULES pre-load specified modules MODULES
--themes=THEMES install THEMES [default=starfield]
-v, --verbose print verbose messages.
--allow-floppy make the drive also bootable as floppy (default
for fdX devices). May break on some BIOSes.
--auto-nvram only update NVRAM variables if possible. This
option is only available on EFI and IEEE1275
targets.
--boot-directory=DIR install GRUB images under the directory DIR/grub
instead of the boot/grub directory
--bootloader-id=ID the ID of bootloader. This option is only
available on EFI and Macs.
--core-compress=xz|none|auto
choose the compression to use for core image
--disk-module=MODULE disk module to use (biosdisk or native). This
option is only available on BIOS target.
--efi-directory=DIR use DIR as the EFI System Partition root.
--force install even if problems are detected
--force-file-id use identifier file even if UUID is available
--label-bgcolor=COLOR use COLOR for label background
--label-color=COLOR use COLOR for label
--label-font=FILE use FILE as font for label
--macppc-directory=DIR use DIR for PPC MAC install.
--no-bootsector do not install bootsector
--no-extra-removable Do not install bootloader code to the removable
media path. This option is only available on EFI.
--no-nvram don't update the `boot-device'/`Boot*' NVRAM
variables. This option is only available on EFI
and IEEE1275 targets.
--no-rs-codes Do not apply any reed-solomon codes when
embedding core.img. This option is only available
on x86 BIOS targets.
--no-uefi-secure-boot do not install an image usable with UEFI Secure
Boot, even if the system was currently started
using it. This option is only available on EFI.
--product-version=STRING use STRING as product version
--recheck delete device map if it already exists
--removable the installation device is removable. This option
is only available on EFI.
-s, --skip-fs-probe do not probe for filesystems in DEVICE
--target=TARGET install GRUB for TARGET platform
[default=x86_64-efi]; available targets: arm-efi,
arm-uboot, arm64-efi, i386-coreboot, i386-efi,
i386-ieee1275, i386-multiboot, i386-pc,
i386-qemu, i386-xen, ia64-efi, mips-arc,
mips-qemu_mips, mipsel-arc, mipsel-loongson,
mipsel-qemu_mips, powerpc-ieee1275,
sparc64-ieee1275, x86_64-efi, x86_64-xen
--uefi-secure-boot install an image usable with UEFI Secure Boot.
This option is only available on EFI and if the
grub-efi-amd64-signed package is installed.
-?, --help give this help list
--usage give a short usage message
-V, --version print program version
Mandatory or optional arguments to long options are also mandatory or optional
for any corresponding short options.
INSTALL_DEVICE must be system device filename.
grub-install copies GRUB images into boot/grub. On some platforms, it may
also install GRUB into the boot sector.
Report bugs to <[email protected]>.
It generates a grub config file.
$ grub-mkconfig --help
Usage: grub-mkconfig [OPTION]
Generate a grub config file
-o, --output=FILE output generated config to FILE [default=stdout]
-h, --help print this message and exit
-v, --version print the version information and exit
Report bugs to <[email protected]>.
It creates the necessary links and cache to the most recent shared libraries found in the directories specified on the command line, in the file /etc/ld.so.conf, and in the trusted directories, /lib and /usr/lib (on some 64-bit architectures such as x86-64, lib and /usr/lib are the trusted directories for 32-bit libraries, while /lib64 and /usr/lib64 are used for 64-bit libraries).
$ ldconfig --help
Usage: ldconfig.real [OPTION...]
Configure Dynamic Linker Run Time Bindings.
-c, --format=FORMAT Format to use: new, old or compat (default)
-C CACHE Use CACHE as cache file
-f CONF Use CONF as configuration file
-i, --ignore-aux-cache Ignore auxiliary cache file
-l Manually link individual libraries.
-n Only process directories specified on the command
line. Don't build cache.
-N Don't build cache
-p, --print-cache Print cache
-r ROOT Change to and use ROOT as root directory
-v, --verbose Generate verbose messages
-X Don't update symbolic links
-?, --help Give this help list
--usage Give a short usage message
-V, --version Print program version
Mandatory or optional arguments to long options are also mandatory or optional
for any corresponding short options.
For bug reporting instructions, please see:
<https://bugs.launchpad.net/ubuntu/+source/glibc/+bugs>.
It prints the shared objects (shared libraries) required by each program or shared object specified on the command line.
$ ldd --help
Usage: ldd [OPTION]... FILE...
--help print this help and exit
--version print version information and exit
-d, --data-relocs process data relocations
-r, --function-relocs process data and function relocations
-u, --unused print unused direct dependencies
-v, --verbose print all information
For bug reporting instructions, please see:
<https://bugs.launchpad.net/ubuntu/+source/glibc/+bugs>.
It displays information about one or more object files.
$ objdump --help
Usage: objdump <option(s)> <file(s)>
Display information from object <file(s)>.
At least one of the following switches must be given:
-a, --archive-headers Display archive header information
-f, --file-headers Display the contents of the overall file header
-p, --private-headers Display object format specific file header contents
-P, --private=OPT,OPT... Display object format specific contents
-h, --[section-]headers Display the contents of the section headers
-x, --all-headers Display the contents of all headers
-d, --disassemble Display assembler contents of executable sections
-D, --disassemble-all Display assembler contents of all sections
-S, --source Intermix source code with disassembly
-s, --full-contents Display the full contents of all sections requested
-g, --debugging Display debug information in object file
-e, --debugging-tags Display debug information using ctags style
-G, --stabs Display (in raw form) any STABS info in the file
-W[lLiaprmfFsoRtUuTgAckK] or
--dwarf[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,
=frames-interp,=str,=loc,=Ranges,=pubtypes,
=gdb_index,=trace_info,=trace_abbrev,=trace_aranges,
=addr,=cu_index,=links,=follow-links]
Display DWARF info in the file
-t, --syms Display the contents of the symbol table(s)
-T, --dynamic-syms Display the contents of the dynamic symbol table
-r, --reloc Display the relocation entries in the file
-R, --dynamic-reloc Display the dynamic relocation entries in the file
@<file> Read options from <file>
-v, --version Display this program's version number
-i, --info List object formats and architectures supported
-H, --help Display this information
The following switches are optional:
-b, --target=BFDNAME Specify the target object format as BFDNAME
-m, --architecture=MACHINE Specify the target architecture as MACHINE
-j, --section=NAME Only display information for section NAME
-M, --disassembler-options=OPT Pass text OPT on to the disassembler
-EB --endian=big Assume big endian format when disassembling
-EL --endian=little Assume little endian format when disassembling
--file-start-context Include context from start of file (with -S)
-I, --include=DIR Add DIR to search list for source files
-l, --line-numbers Include line numbers and filenames in output
-F, --file-offsets Include file offsets when displaying information
-C, --demangle[=STYLE] Decode mangled/processed symbol names
The STYLE, if specified, can be `auto', `gnu',
`lucid', `arm', `hp', `edg', `gnu-v3', `java'
or `gnat'
--recurse-limit Enable a limit on recursion whilst demangling. [Default]
--no-recurse-limit Disable a limit on recursion whilst demangling
-w, --wide Format output for more than 80 columns
-z, --disassemble-zeroes Do not skip blocks of zeroes when disassembling
--start-address=ADDR Only process data whose address is >= ADDR
--stop-address=ADDR Only process data whose address is <= ADDR
--prefix-addresses Print complete address alongside disassembly
--[no-]show-raw-insn Display hex alongside symbolic disassembly
--insn-width=WIDTH Display WIDTH bytes on a single line for -d
--adjust-vma=OFFSET Add OFFSET to all displayed section addresses
--special-syms Include special symbols in symbol dumps
--inlines Print all inlines for source line (with -l)
--prefix=PREFIX Add PREFIX to absolute paths for -S
--prefix-strip=LEVEL Strip initial directory names for -S
--dwarf-depth=N Do not display DIEs at depth N or greater
--dwarf-start=N Display DIEs starting with N, at the same depth
or deeper
--dwarf-check Make additional dwarf internal consistency checks.
objdump: supported targets: elf64-x86-64 elf32-i386 elf32-iamcu elf32-x86-64 a.out-i386-linux pei-i386 pei-x86-64 elf64-l1om elf64-k1om elf64-little elf64-big elf32-little elf32-big pe-x86-64 pe-bigobj-x86-64 pe-i386 plugin srec symbolsrec verilog tekhex binary ihex
objdump: supported architectures: i386 i386:x86-64 i386:x64-32 i8086 i386:intel i386:x86-64:intel i386:x64-32:intel i386:nacl i386:x86-64:nacl i386:x64-32:nacl iamcu iamcu:intel l1om l1om:intel k1om k1om:intel plugin
The following i386/x86-64 specific disassembler options are supported for use
with the -M switch (multiple options should be separated by commas):
x86-64 Disassemble in 64bit mode
i386 Disassemble in 32bit mode
i8086 Disassemble in 16bit mode
att Display instruction in AT&T syntax
intel Display instruction in Intel syntax
att-mnemonic
Display instruction in AT&T mnemonic
intel-mnemonic
Display instruction in Intel mnemonic
addr64 Assume 64bit address size
addr32 Assume 32bit address size
addr16 Assume 16bit address size
data32 Assume 32bit data size
data16 Assume 16bit data size
suffix Always display instruction suffix in AT&T syntax
amd64 Display instruction in AMD64 ISA
intel64 Display instruction in Intel64 ISA
Report bugs to <http://www.sourceware.org/bugzilla/>.
It displays information about one or more ELF format object files. The options control what particular information to display.
$ readelf --help
Usage: readelf <option(s)> elf-file(s)
Display information about the contents of ELF format files
Options are:
-a --all Equivalent to: -h -l -S -s -r -d -V -A -I
-h --file-header Display the ELF file header
-l --program-headers Display the program headers
--segments An alias for --program-headers
-S --section-headers Display the sections' header
--sections An alias for --section-headers
-g --section-groups Display the section groups
-t --section-details Display the section details
-e --headers Equivalent to: -h -l -S
-s --syms Display the symbol table
--symbols An alias for --syms
--dyn-syms Display the dynamic symbol table
-n --notes Display the core notes (if present)
-r --relocs Display the relocations (if present)
-u --unwind Display the unwind info (if present)
-d --dynamic Display the dynamic section (if present)
-V --version-info Display the version sections (if present)
-A --arch-specific Display architecture specific information (if any)
-c --archive-index Display the symbol/file index in an archive
-D --use-dynamic Use the dynamic section info when displaying symbols
-x --hex-dump=<number|name>
Dump the contents of section <number|name> as bytes
-p --string-dump=<number|name>
Dump the contents of section <number|name> as strings
-R --relocated-dump=<number|name>
Dump the contents of section <number|name> as relocated bytes
-z --decompress Decompress section before dumping it
-w[lLiaprmfFsoRtUuTgAckK] or
--debug-dump[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,
=frames-interp,=str,=loc,=Ranges,=pubtypes,
=gdb_index,=trace_info,=trace_abbrev,=trace_aranges,
=addr,=cu_index,=links,=follow-links]
Display the contents of DWARF debug sections
--dwarf-depth=N Do not display DIEs at depth N or greater
--dwarf-start=N Display DIEs starting with N, at the same depth
or deeper
-I --histogram Display histogram of bucket list lengths
-W --wide Allow output width to exceed 80 characters
@<file> Read options from <file>
-H --help Display this information
-v --version Display the version number of readelf
Report bugs to <http://www.sourceware.org/bugzilla/>
It is a stub for running grub-mkconfig -o /boot/grub/grub.cfg to generate a grub2 config file.
$ update-grub --help
Usage: grub-mkconfig [OPTION]
Generate a grub config file
-o, --output=FILE output generated config to FILE [default=stdout]
-h, --help print this message and exit
-v, --version print the version information and exit
Report bugs to <[email protected]>.
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