System information
|
Command
|
Description
|
# arch
|
show
architecture of machine(1)
|
# cal 2007
|
show the
timetable of 2007
|
# cat /proc/cpuinfo
|
show
information CPU info
|
# cat /proc/interrupts
|
show
interrupts
|
# cat /proc/meminfo
|
verify memory
use
|
# cat /proc/swaps
|
show file(s)
swap
|
# cat /proc/version
|
show version
of the kernel
|
# cat /proc/net/dev
|
show network
adpters and statistics
|
# cat /proc/mounts
|
show mounted
file system(s)
|
# clock -w
|
save date
changes on BIOS
|
# date
|
show system
date
|
# date 041217002007.00
|
set date and
time - MonthDayhoursMinutesYear.Seconds
|
# dmidecode -q
|
show hardware
system components - (SMBIOS / DMI)
|
# hdparm -i /dev/hda
|
displays the
characteristics of a hard-disk
|
# hdparm -tT /dev/sda
|
perform test
reading on a hard-disk
|
# lspci -tv
|
display PCI
devices
|
# lsusb -tv
|
show USB
devices
|
# uname -m
|
show
architecture of machine(2)
|
# uname -r
|
show used
kernel version
|
|
|
|
Shutdown, Restart and Logout of a
system
|
Command
|
Description
|
# init 0
|
|
# logout
|
leaving
session
|
# reboot
|
|
# shutdown -h now
|
|
# shutdown -h 16:30 &
|
planned
shutdown of the system
|
# shutdown -c
|
cancel a
planned shutdown of the system
|
# shutdown -r now
|
|
# telinit 0
|
|
|
|
|
|
Command
|
Description
|
# cd /home
|
enter to
directory '/ home'
|
# cd ..
|
|
# cd ../..
|
|
# cd
|
|
# cd ~user1
|
|
# cd -
|
|
# cp file1 file2
|
|
# cp dir/* .
|
copy all
files of a directory within the current work directory
|
# cp -a /tmp/dir1 .
|
copy a
directory within the current work directory
|
# cp -a dir1 dir2
|
|
# cp file file1
|
outputs the
mime type of the file as text
|
# iconv -l
|
|
# iconv -f fromEncoding -t toEncoding inputFile >
outputFile
|
converting
the coding of characters from one format to another
|
# find . -maxdepth 1 -name *.jpg -print -exec convert
|
batch resize
files in the current directory and send them to a thumbnails directory
(requires convert from Imagemagick)
|
# ln -s file1 lnk1
|
create a
symbolic link to file or directory
|
# ln file1 lnk1
|
create a
physical link to file or directory
|
# ls
|
|
# ls -F
|
|
# ls -l
|
show details
of files and directory
|
# ls -a
|
|
# ls * 0-9 *
|
show files
and directory containing numbers
|
# lstree
|
show files
and directories in a tree starting from root(2)
|
# mkdir dir1
|
create a
directory called 'dir1'
|
# mkdir dir1 dir2
|
create two
directories simultaneously
|
# mkdir -p /tmp/dir1/dir2
|
|
# mv dir1 new_dir
|
rename / move
a file or directory
|
# pwd
|
show the path
of work directory
|
# rm -f file1
|
delete file
called 'file1'
|
# rm -rf dir1
|
remove a
directory called 'dir1' and contents recursively
|
# rm -rf dir1 dir2
|
remove two
directories and their contents recursively
|
# rmdir dir1
|
delete
directory called 'dir1'
|
# touch -t 0712250000 file1
|
modify
timestamp of a file or directory - (YYMMDDhhmm)
|
# tree
|
show files
and directories in a tree starting from root(1)
|
|
|
|
|
Command
|
Description
|
# find / -name file1
|
search file
and directory into root filesystem from '/'
|
# find / -user user1
|
search files
and directories belonging to 'user1'
|
# find /home/user1 -name \*.bin
|
search files
with '. bin' extension within directory '/ home/user1'
|
# find /usr/bin -type f -atime +100
|
search binary
files are not used in the last 100 days
|
# find /usr/bin -type f -mtime -10
|
search files
created or changed within 10 days
|
# find / -name *.rpm -exec chmod 755 '{}' \;
|
search files
with '.rpm' extension and modify permits
|
# find / -xdev -name \*.rpm
|
search files
with '.rpm' extension ignoring removable partitions as cdrom, pen-drive,
etc.…
|
# locate \*.ps
|
find files
with the '.ps' extension - first run 'updatedb' com d
|
# whereis halt
|
show location
of a binary file, source or
|
# which halt
|
show full
path to a binary / executable
|
|
|
|
|
Com d
|
Description
|
# fuser -km /mnt/hda2
|
force umount
when the device is busy
|
# mount /dev/hda2 /mnt/hda2
|
mount disk
called hda2 - verify existence of the directory '/ mnt/hda2'
|
# mount /dev/fd0 /mnt/floppy
|
|
# mount /dev/cdrom /mnt/cdrom
|
|
# mount /dev/hdc /mnt/cdrecorder
|
|
# mount /dev/hdb /mnt/cdrecorder
|
|
# mount -o loop file.iso /mnt/cdrom
|
mount a file
or iso image
|
# mount -t vfat /dev/hda5 /mnt/hda5
|
mount a
Windows FAT32 file system
|
# mount /dev/sda1 /mnt/usbdisk
|
mount a usb
pen-drive or flash-drive
|
# mount -t smbfs -o username=user,password=pass
//WinClient/share /mnt/share
|
mount a
windows network share
|
# umount /dev/hda2
|
unmount disk
called hda2 - exit from mount point '/ mnt/hda2' first
|
# umount -n /mnt/hda2
|
run umount
without writing the file /etc/mtab - useful when the file is read-only or
the hard disk is full
|
|
|
|
Command
|
Description
|
# df -h
|
show list of
partitions mounted
|
# dpkg-query -W -f='${Installed-Size;10}t${Package}n' |
sort -k1,1n
|
show the used
space by installed deb packages, sorting by size (debian, ubuntu and alike)
|
# du -sh dir1
|
estimate
space used by directory 'dir1'
|
# du -sk * | sort -rn
|
show size of
the files and directories sorted by size
|
# ls -lSr |more
|
show size of
the files and directories ordered by size
|
# rpm -q -a --qf '%10{SIZE}t%{NAME}n' | sort -k1,1n
|
show space
used by rpm packages installed sorted by size (fedora, redhat and like)
|
|
|
|
|
Command
|
Description
|
# chage -E 2005-12-31 user1
|
set deadline
for user password
|
# groupadd group
|
|
# groupdel group
|
|
# groupmod -n moon sun
|
rename a
group from moon to sun
|
# grpck
|
check correct
syntax and file format of '/etc/group' and groups existence
|
# newgrp - group
|
log into a
new group to change default group of newly created files
|
# passwd
|
|
# passwd user1
|
change a user
password (only by root)
|
# pwck
|
check correct
syntax and file format of '/etc/passwd' and users existence
|
# useradd -c "User Linux" -g admin -d
/home/user1 -s /bin/bash user1
|
create a new
user "user1" belongs "admin" group
|
# useradd user1
|
|
# userdel -r user1
|
delete a user
( '-r' eliminates home directory)
|
# usermod -c "User FTP" -g system -d
/ftp/user1 -s /bin/nologin user1
|
|
|
|
|
|
Command
|
Description
|
# chgrp group1 file1
|
|
# chmod ugo+rwx directory1
|
set
permissions reading (r), write (w) and (x) access to users owner (u) group
(g) and others (o)
|
# chmod go-rwx directory1
|
remove
permits reading (r), write (w) and (x) access to users group (g) and others
(or
|
# chmod u+s /bin/file1
|
set SUID bit
on a binary file - the user that running that file gets same privileges as
owner
|
# chmod u-s /bin/file1
|
disable SUID
bit on a binary file
|
# chmod g+s /home/public
|
set SGID bit
on a directory - similar to SUID but for directory
|
# chmod g-s /home/public
|
disable SGID
bit on a directory
|
# chmod o+t /home/public
|
set STIKY bit
on a directory - allows files deletion only to legitimate owners
|
# chmod o-t /home/public
|
disable STIKY
bit on a directory
|
# chown user1 file1
|
|
# chown -R user1 directory1
|
change user
owner of a directory and all the files and directories contained inside
|
# chown user1:group1 file1
|
change user
and group ownership of a file
|
# find / -perm -u+s
|
view all
files on the system with SUID configured
|
# ls -lh
|
|
# ls /tmp | pr -T5 -W$COLUMNS
|
divide
terminal into 5 columns
|
|
|
|
Special Attributes on files
|
Command
|
Description
|
# chattr +a file1
|
allows write
opening of a file only append mode
|
# chattr +c file1
|
allows that a
file is compressed / decompressed automatically by the kernel
|
# chattr +d file1
|
makes sure
that the program ignores Dump the files during backup
|
# chattr +i file1
|
makes it an
immutable file, which can not be removed, altered, renamed or linked
|
# chattr +s file1
|
allows a file
to be deleted safely
|
# chattr +S file1
|
makes sure
that if a file is modified changes are written in synchronous mode as with
sync
|
# chattr +u file1
|
allows you to
recover the contents of a file even if it is canceled
|
# lsattr
|
|
|
|
Archives and compressed files
|
Command
|
Description
|
# bunzip2 file1.bz2
|
decompress a
file called 'file1.bz2'
|
# bzip2 file1
|
compress a
file called 'file1'
|
# gunzip file1.gz
|
decompress a
file called 'file1.gz'
|
# gzip file1
|
compress a
file called 'file1'
|
# gzip -9 file1
|
compress with
maximum compression
|
# rar a file1.rar test_file
|
create an
archive rar called 'file1.rar'
|
# rar a file1.rar file1 file2 dir1
|
compress
'file1', 'file2' and 'dir1' simultaneously
|
# rar x file1.rar
|
|
# tar -cvf archive.tar file1
|
create a
uncompressed tarball
|
# tar -cvf archive.tar file1 file2 dir1
|
create an
archive containing 'file1', 'file2' and 'dir1'
|
# tar -tf archive.tar
|
show contents
of an archive
|
# tar -xvf archive.tar
|
|
# tar -xvf archive.tar -C /tmp
|
extract a
tarball into / tmp
|
# tar -cvfj archive.tar.bz2 dir1
|
create a
tarball compressed into bzip2
|
# tar -xvfj archive.tar.bz2
|
decompress a
compressed tar archive in bzip2
|
# tar -cvfz archive.tar.gz dir1
|
create a
tarball compressed into gzip
|
# tar -xvfz archive.tar.gz
|
decompress a
compressed tar archive in gzip
|
# unrar x file1.rar
|
|
# unzip file1.zip
|
|
# zip file1.zip file1
|
create an
archive compressed in zip
|
# zip -r file1.zip file1 file2 dir1
|
compress in
zip several files and directories simultaneously
|
|
|
|
RPM Packages ( Fedora, Red Hat and
like)
|
Command
|
Description
|
# rpm -ivh package.rpm
|
|
# rpm -ivh --nodeeps package.rpm
|
install a rpm
package ignoring dependencies requests
|
# rpm -U package.rpm
|
upgrade a rpm
package without changing configuration files
|
# rpm -F package.rpm
|
upgrade a rpm
package only if it is already installed
|
# rpm -e package
|
|
# rpm -qa
|
show all rpm
packages installed on the system
|
# rpm -qa | grep httpd
|
show all rpm
packages with the name "httpd"
|
# rpm -qi package
|
obtain
information on a specific package installed
|
# rpm -qg "System Environment/Daemons"
|
show rpm
packages of a group software
|
# rpm -ql package
|
show list of
files provided by a rpm package installed
|
# rpm -qc package
|
show list of
configuration files provided by a rpm package installed
|
# rpm -q package --whatrequires
|
show list of
dependencies required for a rpm packet
|
# rpm -q package --whatprovides
|
show
capability provided by a rpm package
|
# rpm -q package --scripts
|
show scripts
started during installation / removal
|
# rpm -q package --changelog
|
show history
of revisions of a rpm package
|
# rpm -qf /etc/httpd/conf/httpd.conf
|
verify which
rpm package belongs to a given file
|
# rpm -qp package.rpm
-l
|
show list of
files provided by a rpm package not yet installed
|
# rpm --import /media/cdrom/RPM-GPG-KEY
|
import
public-key digital signature
|
# rpm --checksig package.rpm
|
verify the
integrity of a rpm package
|
# rpm -qa gpg-pubkey
|
verify
integrity of all rpm packages installed
|
# rpm -V package
|
check file
size, permissions, type, owner, group, MD5 checksum and last modification
|
# rpm -Va
|
check all rpm
packages installed on the system - use with caution
|
# rpm -Vp package.rpm
|
verify a rpm
package not yet installed
|
# rpm -ivh /usr/src/redhat/RPMS/`arch`/ package.rpm
|
install a
package built from a rpm source
|
# rpm2cpio package.rpm
| cpio --extract --make-directories
*bin*
|
extract
executable file from a rpm package
|
# rpmbuild --rebuild package.src.rpm
|
build a rpm
package from a rpm source
|
|
|
|
YUM packages tool (Fedora, RedHat and
alike)
|
Command
|
Description
|
# yum -y install package
|
download and
install a rpm package
|
# yum localinstall package.rpm
|
That will
install an RPM, and try to resolve all the dependencies for you using your
repositories.
|
# yum -y update
|
update all
rpm packages installed on the system
|
# yum update package
|
|
# yum remove package
|
|
# yum list
|
list all
packages installed on the system
|
# yum search package
|
find a
package on rpm repository
|
# yum clean package
|
clean up rpm
cache erasing downloaded packages
|
# yum clean headers
|
remove all
files headers that the system uses to resolve dependency
|
# yum clean all
|
remove from
the cache packages and headers files
|
|
|
|
DEB packages (Debian, Ubuntu and like)
|
Command
|
Description
|
# dpkg -i package.deb
|
install /
upgrade a deb package
|
# dpkg -r package
|
remove a deb
package from the system
|
# dpkg -l
|
show all deb
packages installed on the system
|
# dpkg -l | grep httpd
|
show all deb
packages with the name "httpd"
|
# dpkg -s package
|
obtain
information on a specific package installed on system
|
# dpkg -L package
|
show list of
files provided by a package installed on system
|
# dpkg --contents package.deb
|
show list of
files provided by a package not yet installed
|
# dpkg -S /bin/ping
|
verify which
package belongs to a given file
|
|
|
|
APT packages tool (Debian, Ubuntu and
alike)
|
Command
|
Description
|
# apt-cache search package
|
returns list
of packages which corresponds string "searched-packages"
|
# apt-cdrom install package
|
install /
upgrade a deb package from cdrom
|
# apt-get install package
|
install /
upgrade a deb package
|
# apt-get update
|
|
# apt-get upgrade
|
upgrade all
of the installed packages
|
# apt-get remove package
|
remove a deb
package from system
|
# apt-get check
|
verify
correct resolution of dependencies
|
# apt-get clean
|
clean up
cache from packages downloaded
|
|
|
|
PAC packages tool (Arch, Frugalware and alike)
|
Command
|
Description
|
# pac -S name
|
Install
package 'name' with dependencies
|
# pac -R name
|
Delete
package 'name' and all files of it
|
|
|
|
|
Command
|
Description
|
# cat file1
|
view the
contents of a file starting from the first row
|
# head -2 file1
|
view first
two lines of a file
|
# less file1
|
similar to
'more' com d but which allows backward movement in the file as well as
forward movement
|
# more file1
|
view content
of a file along
|
# tac file1
|
view the
contents of a file starting from the last line
|
# tail -2 file1
|
view last two
lines of a file
|
# tail -f /var/log/messages
|
view in real
time what is added to a file
|
|
|
|
|
Command
|
Description
|
# cat example.txt | awk 'NR%2==1'
|
remove all
even lines from example.txt
|
# echo a b c | awk '{print $1}'
|
view the
first column of a line
|
# echo a b c | awk '{print $1,$3}'
|
view the
first and third column of a line
|
# cat -n file1
|
|
# comm -1 file1 file2
|
compare
contents of two files by deleting only unique lines from 'file1'
|
# comm -2 file1 file2
|
compare
contents of two files by deleting only unique lines from 'file2'
|
# comm -3 file1 file2
|
compare
contents of two files by deleting only the lines that appear on both files
|
# diff file1 file2
|
find
differences between two files
|
# grep Aug /var/log/messages
|
look up words
"Aug" on file '/var/log/messages'
|
# grep ^Aug /var/log/messages
|
look up words
that begin with "Aug" on file '/var/log/messages'
|
# grep 0-9 /var/log/messages
|
select from
file '/var/log/messages' all lines that contain numbers
|
# grep Aug -R /var/log/*
|
search string
"Aug" at directory '/var/log' and below
|
# paste file1 file2
|
merging
contents of two files for columns
|
# paste -d '+' file1 file2
|
merging
contents of two files for columns with '+' delimiter on the center
|
# sdiff file1 file2
|
find
differences between two files and merge interactively alike
"diff"
|
# sed 's/string1/string2/g' example.txt
|
replace
"string1" with "string2" in example.txt
|
# sed '/^$/d' example.txt
|
remove all
blank lines from example.txt
|
# sed '/ *#/d; /^$/d' example.txt
|
remove
comments and blank lines from example.txt
|
# sed -e '1d' exampe.txt
|
eliminates
the first line from file example.txt
|
# sed -n '/string1/p'
|
view only
lines that contain the word "string1"
|
# sed -e 's/ *$//' example.txt
|
remove empty
characters at the end of each row
|
# sed -e 's/string1//g' example.txt
|
remove only
the word "string1" from text and leave intact all
|
# sed -n '1,5p' example.txt
|
print from
1th to 5th row of example.txt
|
# sed -n '5p;5q' example.txt
|
print row
number 5 of example.txt
|
# sed -e 's/00*/0/g' example.txt
|
replace more
zeros with a single zero
|
# sort file1 file2
|
sort contents
of two files
|
# sort file1 file2 | uniq
|
sort contents
of two files omitting lines repeated
|
# sort file1 file2 | uniq -u
|
sort contents
of two files by viewing only unique line
|
# sort file1 file2 | uniq -d
|
sort contents
of two files by viewing only duplicate line
|
# echo 'word' | tr ' :lower: ' ' :upper: '
|
convert from
lower case in upper case
|
|
|
|
Character set and Format file
conversion
|
Command
|
Description
|
# dos2unix filedos.txt fileunix.txt
|
convert a
text file format from MSDOS to UNIX
|
# recode ..HTML < page.txt > page.html
|
convert a
text file to html
|
# recode -l | more
|
show all
available formats conversion
|
# unix2dos fileunix.txt filedos.txt
|
convert a
text file format from UNIX to MSDOS
|
|
|
|
|
Command
|
Description
|
# badblocks -v /dev/hda1
|
check bad
blocks on disk hda1
|
# dosfsck /dev/hda1
|
repair /
check integrity of dos filesystems on disk hda1
|
# e2fsck /dev/hda1
|
repair /
check integrity of ext2 filesystem on disk hda1
|
# e2fsck -j /dev/hda1
|
repair /
check integrity of ext3 filesystem on disk hda1
|
# fsck /dev/hda1
|
repair /
check integrity of linux filesystem on disk hda1
|
# fsck.ext2 /dev/hda1
|
repair /
check integrity of ext2 filesystem on disk hda1
|
# fsck.ext3 /dev/hda1
|
repair /
check integrity of ext3 filesystem on disk hda1
|
# fsck.vfat /dev/hda1
|
repair /
check integrity of fat filesystem on disk hda1
|
# fsck.msdos /dev/hda1
|
repair /
check integrity of dos filesystem on disk hda1
|
|
|
|
|
Command
|
Description
|
# fdformat -n /dev/fd0
|
|
# mke2fs /dev/hda1
|
create a
filesystem type linux ext2 on hda1 partition
|
# mke2fs -j /dev/hda1
|
create a
filesystem type linux ext3 (journal) on hda1 partition
|
# mkfs /dev/hda1
|
create a filesystem
type linux on hda1 partition
|
# mkfs -t vfat 32 -F /dev/hda1
|
create a
FAT32 filesystem
|
# mkswap /dev/hda3
|
|
|
|
|
|
Command
|
Description
|
# mkswap /dev/hda3
|
|
# swapon /dev/hda3
|
activating a
new swap partition
|
# swapon /dev/hda2 /dev/hdb3
|
activate two
swap partitions
|
|
|
|
|
Command
|
Description
|
# find /var/log -name '*.log' | tar cv --files-from=- |
bzip2 > log.tar.bz2
|
find all
files with '.log' extention and make an bzip archive
|
# find /home/user1 -name '*.txt' | xargs cp -av
--target-directory=/home/backup/ --parents
|
find and copy
all files with '.txt' extention from a directory to another
|
# dd bs=1M if=/dev/hda | gzip | ssh user@ip_addr 'dd
of=hda.gz'
|
make a backup
of a local hard disk on remote host via ssh
|
# dd if=/dev/sda of=/tmp/file1
|
backup
content of the harddrive to a file
|
# dd if=/dev/hda of=/dev/fd0 bs=512 count=1
|
make a copy
of MBR (Master Boot Record) to floppy
|
# dd if=/dev/fd0 of=/dev/hda bs=512 count=1
|
restore MBR
from backup copy saved to floppy
|
# dump -0aj -f /tmp/home0.bak /home
|
make a full
backup of directory '/home'
|
# dump -1aj -f /tmp/home0.bak /home
|
make a
incremental backup of directory '/home'
|
# restore -if /tmp/home0.bak
|
restoring a
backup interactively
|
# rsync -rogpav --delete /home /tmp
|
synchronization
between directories
|
# rsync -rogpav -e ssh --delete /home ip_address:/tmp
|
|
# rsync -az -e ssh --delete ip_addr:/home/public
/home/local
|
synchronize a
local directory with a remote directory via ssh and compression
|
# rsync -az -e ssh --delete /home/local
ip_addr:/home/public
|
synchronize a
remote directory with a local directory via ssh and compression
|
# tar -Puf backup.tar /home/user
|
make a
incremental backup of directory '/home/user'
|
# ( cd /tmp/local/ && tar c . ) | ssh -C
user@ip_addr 'cd /home/share/ && tar x -p'
|
copy content
of a directory on remote directory via ssh
|
# ( tar c /home ) | ssh -C user@ip_addr 'cd
/home/backup-home && tar x -p'
|
copy a local
directory on remote directory via ssh
|
# tar cf - . | (cd /tmp/backup ; tar xf - )
|
local copy
preserving permits and links from a directory to another
|
|
|
|
|
Command
|
Description
|
# cd-paranoia -B
|
rip audio
tracks from a CD to wav files
|
# cd-paranoia --
|
rip first
three audio tracks from a CD to wav files
|
# cdrecord -v gracetime=2 dev=/dev/cdrom -eject
blank=fast -force
|
|
# cdrecord -v dev=/dev/cdrom cd.iso
|
|
# gzip -dc cd_iso.gz | cdrecord dev=/dev/cdrom -
|
burn a
compressed ISO image
|
# cdrecord --scanbus
|
scan bus to
identify the channel scsi
|
# dd if=/dev/hdc | md5sum
|
perform an
md5sum on a device, like a CD
|
# mkisofs /dev/cdrom > cd.iso
|
create an iso
image of cdrom on disk
|
# mkisofs /dev/cdrom | gzip > cd_iso.gz
|
create a
compressed iso image of cdrom on disk
|
# mkisofs -J -allow-leading-dots -R -V
|
create an iso
image of a directory
|
# mount -o loop cd.iso /mnt/iso
|
|
|
|
|
|
Command
|
Description
|
# dhclient eth0
|
active
interface 'eth0' in dhcp mode
|
# ethtool eth0
|
show network
statistics of eth0
|
# host www.example.com
|
lookup
hostname to resolve name to ip address and viceversa
|
# hostname
|
|
# ifconfig eth0
|
show
configuration of an ethernet network card
|
# ifconfig eth0 192.168.1.1 netmask 255.255.255.0
|
|
# ifconfig eth0 promisc
|
configure
'eth0' in promiscuous mode to gather packets (sniffing)
|
# ifdown eth0
|
disable an
interface 'eth0'
|
# ifup eth0
|
activate an
interface 'eth0'
|
# ip link show
|
show link
status of all network interfaces
|
# iwconfig eth1
|
|
# iwlist scan
|
wifi scanning
to display the wireless connections available
|
# mii-tool eth0
|
show link
status of 'eth0'
|
# netstat -tup
|
show all
active network connections and their PID
|
# netstat -tupl
|
show all
network services listening on the system and their PID
|
# netstat -rn
|
show routing
table alike "route -n"
|
# nslookup www.example.com
|
lookup
hostname to resolve name to ip address and viceversa
|
# route -n
|
|
# route add -net 0/0 gw IP_Gateway
|
configure
default gateway
|
# route add -net 192.168.0.0 netmask 255.255.0.0 gw
192.168.1.1
|
configure
static route to reach network '192.168.0.0/16'
|
# route del 0/0 gw IP_gateway
|
|
# echo "1" > /proc/sys/net/ipv4/ip_forward
|
|
# tcpdump tcp port 80
|
|
# whois www.example.com
|
|
|
|
|
Microsoft Windows networks (samba)
|
Command
|
Description
|
# mount -t smbfs -o username=user,password=pass
//WinClient/share /mnt/share
|
mount a
windows network share
|
# nbtscan ip_addr
|
|
# nmblookup -A ip_addr
|
|
# smbclient -L ip_addr/hostname
|
show remote
shares of a windows host
|
# smbget -Rr smb://ip_addr/share
|
like wget can
download files from a host windows via smb
|
|
|
|
|
Command
|
Description
|
# iptables -t filter -L
|
show all
chains of filtering table
|
# iptables -t nat -L
|
show all
chains of nat table
|
# iptables -t filter -F
|
clear all
rules from filtering table
|
# iptables -t nat -F
|
clear all
rules from table nat
|
# iptables -t filter -X
|
delete any
chains created by user
|
# iptables -t filter -A INPUT -p tcp --dport telnet -j
ACCEPT
|
allow telnet
connections to input
|
# iptables -t filter -A OUTPUT -p tcp --dport http -j
DROP
|
block HTTP
connections to output
|
# iptables -t filter -A FORWARD -p tcp --dport pop3 -j
ACCEPT
|
allow POP3
connections to forward chain
|
# iptables -t filter -A INPUT -j LOG --log-prefix
|
|
# iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
|
configure a
PAT (Port Address Traslation) on eth0 masking outbound packets
|
# iptables -t nat -A PREROUTING -d 192.168.0.1 -p tcp -m
tcp --dport 22 -j DNAT --to-destination 10.0.0.2:22
|
redirect
packets addressed to a host to another host
|
|
|
|
|
Command
|
Description
|
# free -m
|
displays
status of RAM in megabytes
|
# kill -9 process_id
|
force closure
of the process and finish it
|
# kill -1 process_id
|
force a
process to reload configuration
|
# last reboot
|
|
# lsmod
|
|
# lsof -p process_id
|
display a
list of files opened by processes
|
# lsof /home/user1
|
displays a
list of open files in a given path system
|
# ps -eafw
|
|
# ps -e -o pid,args --forest
|
displays
linux tasks in a hierarchical mode
|
# pstree
|
Shows a tree
system processes
|
# smartctl -A /dev/hda
|
monitoring
reliability of a hard-disk through SMART
|
# smartctl -i /dev/hda
|
check if
SMART is active on a hard-disk
|
# strace -c ls >/dev/null
|
display
system calls made and received by a process
|
# strace -f -e open ls >/dev/null
|
|
# tail /var/log/dmesg
|
show events
inherent to the process of booting kernel
|
# tail /var/log/messages
|
|
# top
|
display linux
tasks using most cpu
|
# watch -n1 'cat /proc/interrupts'
|
display
interrupts in real-time
|
|
|
|
|
Command
|
Description
|
# alias hh='history'
|
set an alias
for a com d - hh = history
|
# apropos ...keyword
|
display a
list of com ds that pertain to keywords of a program , useful when you know
what your program does, but you don't know the name of the com d
|
# chsh
|
|
# chsh --list-shells
|
nice com d to
know if you have to remote into another box
|
# gpg -c file1
|
encrypt a
file with GNU Privacy Guard
|
# gpg file1.gpg
|
decrypt a
file with GNU Privacy Guard
|
# ldd /usr/bin/ssh
|
show shared
libraries required by ssh program
|
# ping
|
display the
on-line ual pages for example on
ping com d - use '-k' option to find any related com ds
|
# mkbootdisk --device /dev/fd0 `uname -r`
|
|
# wget -r www.example.com
|
download an
entire web site
|
# wget -c www.example.com/file.iso
|
download a
file with the ability to stop the download and resume later
|
# echo 'wget -c www.example.com/files.iso' | at 09:00
|
start a
download at any given time
|
# whatis ...keyword
|
displays
description of what a program does
|
# who -a
|
show who is
logged on, and print: time of last system boot, dead processes, system
login processes, active processes spawned by init, current runlevel, last
system clock change
|
|