1. a. Eject CD ROM drive: eject or eject /dev/cdrom
b. Insert CD Tray:
mount /dev/cdrom
2. Copy file: cp <source location> <destination
location>
3. Delete file: rm 'file location' such that: rm
'/media/SOFTWARE/ubuntu 8.04(deb packages)/a.txt'
4. To remove a directory along with all of its contents: rm
-fr 'directory location'
5. To uninstall packages: apt-get remove <package
name>
6. To install packages: apt-get install <package
name>]
7. The mkdir command
will allow you to create directories. Example: mkdir
'/home/rubel/Desktop/music' will create a directory called "music" on
desktop.
8. The cd command will allow you to change directories. When
you open a terminal you will be in your home directory. To move around the file
system you will use cd. Examples:
* To navigate into
the root directory, use "cd /"
* To navigate to
your home directory, use "cd" or "cd ~"
* To navigate up
one directory level, use "cd .."
* To navigate to
the previous directory (or back), use "cd -"
* To navigate
through multiple levels of directory at once, specify the full directory path
that you want to go to. For example, use, "cd /var/www" to go
directly to the /www subdirectory of /var/. As another example, "cd
~/Desktop" will move you to the Desktop subdirectory inside your home
directory.
9. The mv command will move a file to a different location
or will rename a file.
a. rename a file: mv
/home/rubel/Desktop/a.txt /home/rubel/Desktop/b.txt
b. move a file: mv
/home/rubel/Desktop/a.txt /home/rubel/a.txt
10. The df command displays filesystem disk space usage for
all mounted partitions. "df -h" is probably the most useful - it uses
megabytes (M) and gigabytes (G) instead of blocks to report. (-h means
"human-readable")
11. Searching and Editing Text Files:
a. The grep command
allows you to search inside a number of files for a particular search pattern
and then print matching lines. Example:
grep easy /home/rubel/a.txt search easy from file a.txt
b. The sed (or
Stream EDitor) command allows search and replace of a particular string in a
file. For example, sed s/easy/hard/g /home/rubel/a.txt which replace easy to
hard from the file a.txt
12. Compression:
a. zip -r name_of_file.zip files ; example:
zip -r b.zip /home/rubel/Desktop/build.xml
b. unzip
filename.zip ; example: unzip /home/rubel/Desktop/a.txt.zip
13. To Create an ISO Image from a CD or DVD: cat /dev/cdrom
> /home/rubel/slax.iso
14. Burning a CD on the Command Line with wodim
a. See where the
CDROM/DVDROM is located: wodim --devices
b. To burn an
audio cd from wav files : wodim dev=/dev/cdrw driveropts=burnfree -v -audio
[wav files...]
c. Blanking a
CD/RW : wodim -vv dev=/dev/cdrw
blank=all
15.Shutdown, Restart and Logout of a system:
a. # init
0 shutdown system(2)
b. #
logout leaving session
c. #
reboot reboot(2)
d. #
shutdown -h now shutdown system(1)
e. #
shutdown -h 16:30 & planned shutdown of the system at 16:30
f. #
shutdown -c cancel a planned
shutdown of the system
g. #
shutdown -r now reboot(1)
h. #
telinit 0 shutdown system(3)
16. System information:
a. #
arch show architecture of machine(1) [man]
b. # cal
2009 show the timetable of 2009 [man]
c. # cat
/proc/cpuinfo show information CPU
info [man]
d. # cat
/proc/interrupts show
interrupts [man]
e. # cat
/proc/meminfo verify memory
use [man]
f. # cat
/proc/swaps show file(s) swap [man]
g. # cat
/proc/version show version of the
kernel [man]
h. # cat
/proc/net/dev show network adpters and
statistics [man]
i. # cat
/proc/mounts show mounted file
system(s) [man]
j. # clock
-w save date changes on BIOS [man]
k. # date show system date [man]
l. # date
041217002007.00 set date and time -MonthDayhoursMinutesYear.Seconds [man]
m. # dmidecode
-q show hardware system components -
(SMBIOS / DMI) [man]
n. # hdparm
-i /dev/hda displays the
characteristics of a hard-disk [man]
o. # hdparm
-tT /dev/sda perform test reading
on a hard-disk [man]
p. # lspci
-tv display PCI devices [man]
q. # lsusb
-tv show USB devices [man]
r. # uname
-m show architecture of machine(2) [man]
s. # uname
-r show used kernel version [man]
17. Files and Directory:
1. # cd
/home enter to directory '/ home' [man]
2. # cd .. go back one level [man]
3. # cd
../.. go back two levels [man]
4. # cd go to home directory [man]
5. # cd
~user1 go to home
directory [man]
6. # cd - go to previous directory [man]
7. # cp
file1 file2 copying a file [man]
8. # cp
dir/* . copy all files of a directory
within the current work directory [man]
9. # cp -a
/tmp/dir1 . copy a directory within the
current work directory [man]
10. # cp -a
dir1 dir2 copy a directory [man]
11. # cp
file file1 outputs the mime type
of the file as text [man]
12. # iconv
-l lists known encodings [man]
13. # iconv
-f fromEncoding -t toEncoding inputFile > outputFile converting the coding of characters from one format to another [man]
14. # 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)
[man]
15. # ln -s
file1 lnk1 create a symbolic link to
file or directory [man]
16. # ln
file1 lnk1 create a physical link
to file or directory [man]
17. # ls view files of directory [man]
18. # ls -F
view files of directory [man]
19. # ls -l
show details of files and
directory [man]
20. # ls -a
show hidden files [man]
21. # ls
*[0-9]* show files and directory
containing numbers [man]
22. #
lstree show files and directories in
a tree starting from root(2) [man]
23. # mkdir
dir1 create a directory called
'dir1' [man]
24. # mkdir
dir1 dir2 create two directories
simultaneously [man]
25. # mkdir
-p /tmp/dir1/dir2 create a directory
tree [man]
26. # mv
dir1 new_dir rename / move a
file or directory [man]
27. # pwd show the path of work directory [man]
28. # rm -f
file1 delete file called
'file1' [man]
29. # rm
-rf dir1 remove a directory
called 'dir1' and contents recursively
[man]
30. # rm
-rf dir1 dir2 remove two directories and
their contents recursively [man]
31. # rmdir
dir1 delete directory called
'dir1' [man]
32. # touch
-t 0712250000 file1 modify
timestamp of a file or directory - (YYMMDDhhmm) [man]
33. # tree show files and directories in a tree
starting from root(1) [man]
18. File search:
i. # find / -name file1 search file and directory into root filesystem
from '/' [man]
ii.# find /
-user user1 search files and directories
belonging to 'user1' [man]
iii.# find
/home/user1 -name \*.bin search files
with '. bin' extension within directory '/ home/user1' [man]
iv. # find
/usr/bin -type f -atime +100 search
binary files are not used in the last 100 days
[man]
v. # find
/usr/bin -type f -mtime -10 search files
created or changed within 10 days [man]
vi. # find
/ -name *.rpm -exec chmod 755 '{}' \; search
files with '.rpm' extension and modify permits
[man]
vii. # find
/ -xdev -name \*.rpm search files
with '.rpm' extension ignoring removable partitions as cdrom, pen-drive,
etc.… [man]
viii. #
locate \*.ps find files with the
'.ps' extension - first run 'updatedb' command
[man]
ix. #
whereis halt show location of a
binary file, source or man [man]
x. # which
halt show full path to a binary
/ executable [man]
19. Mounting a Filesystem:
a. # fuser
-km /mnt/hda2 force umount when the
device is busy [man]
b. # mount
/dev/hda2 /mnt/hda2 mount disk
called hda2 - verify existence of the directory '/ mnt/hda2' [man]
c. # mount
/dev/fd0 /mnt/floppy mount a
floppy disk [man]
d. # mount
/dev/cdrom /mnt/cdrom mount a cdrom /
dvdrom [man]
e. # mount
/dev/hdc /mnt/cdrecorder mount a cdrw /
dvdrom [man]
f. # mount
/dev/hdb /mnt/cdrecorder mount a cdrw /
dvdrom [man]
g. # mount
-o loop file.iso /mnt/cdrom mount
a file or iso image [man]
h. # mount
-t vfat /dev/hda5 /mnt/hda5 mount
a Windows FAT32 file system [man]
i. # mount
/dev/sda1 /mnt/usbdisk mount a usb
pen-drive or flash-drive [man]
j. # mount
-t smbfs -o username=user,password=pass //WinClient/share /mnt/share mount a windows network share [man]
k. # umount
/dev/hda2 unmount disk called
hda2 - exit from mount point '/ mnt/hda2' first [man]
l. # 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 [man]
20. Disk space:
a. # df
-h show list of partitions mounted [man]
b. # 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) [man]
c. # du -sh
dir1 estimate space used by
directory 'dir1' [man]
d. # du -sk
* | sort -rn show size of the files and
directories sorted by size [man]
e. # ls
-lSr |more show size of the files
and directories ordered by size [man]
f. # rpm -q
-a --qf '%10{SIZE}t%{NAME}n' | sort -k1,1n show
the used space by rpm packages installed sorted by size (fedora, redhat and alike) [man]
20. Users and Groups:
a. # chage
-E 2005-12-31 user1 set deadline for user password [man]
b. #
groupadd [group] create a new
group [man]
c. #
groupdel [group] delete a group [man]
d. #
groupmod -n moon sun rename a group
from moon to sun [man]
e. # grpck check correct syntax and file format of
'/etc/group' and groups existence [man]
f. # newgrp
- [group] log into a new group to change
default group of newly created files
[man]
g. # passwd
change password [man]
h. # passwd
user1 change a user password (only
by root) [man]
i. # pwck check correct syntax and file format of
'/etc/passwd' and users existence [man]
j. #
useradd -c "User Linux" -g admin -d /home/user1 -s /bin/bash user1 create a new user "user1"
belongs "admin" group [man]
k. #
useradd user1 create a new user [man]
l. #
userdel -r user1 delete a user ( '-r'
eliminates home directory) [man]
m. #
usermod -c "User FTP" -g system -d /ftp/user1 -s /bin/nologin user1 change user attributes as description, group
and other [man]
21. Permits on Files:
a. # chgrp group1 file1
change group of files [man]
b. # chmod ugo+rwx directory1 set permissions reading (r), write (w) and (x) access to
users owner (u) group (g) and others (o)
[man]
c. # chmod go-rwx directory1 remove permits reading (r), write (w) and (x) access to
users group (g) and others (or [man]
d. # chmod u+s /bin/file1 set
SUID bit on a binary file - the user that running that file gets same
privileges as owner [man]
e. # chmod u-s /bin/file1 disable
SUID bit on a binary file [man]
f. # chmod g+s /home/public set
SGID bit on a directory - similar to SUID but for directory [man]
g. # chmod g-s /home/public disable
SGID bit on a directory [man]
h. # chmod o+t /home/public set
STIKY bit on a directory - allows files deletion only to legitimate owners [man]
i. # chmod o-t /home/public disable
STIKY bit on a directory [man]
j. # chown user1 file1 change
owner of a file [man]
k. # chown -R user1 directory1 change user owner of a directory and all the files and
directories contained inside [man]
l. # chown user1:group1 file1 change user and group ownership of a file [man]
m. # find / -perm -u+s view
all files on the system with SUID configured
[man]
n. # ls -lh show
permits on files [man]
o. # ls /tmp | pr -T5 -W$COLUMNS divide terminal into 5 columns
[man]
22. Special Attributes on files:
# chattr +a file1 allows write opening of a file only append
mode [man]
# chattr +c file1 allows
that a file is compressed / decompressed automatically by the kernel [man]
# chattr +d file1 makes
sure that the program ignores Dump the files during backup [man]
# chattr +i file1 makes
it an immutable file, which can not be removed, altered, renamed or linked [man]
# chattr +s file1 allows
a file to be deleted safely [man]
# chattr +S file1 makes
sure that if a file is modified changes are written in synchronous mode as with
sync [man]
# chattr +u file1 allows
you to recover the contents of a file even if it is canceled [man]
# lsattr show
specials attributes [man]
23. Archives and compressed files
# bunzip2 file1.bz2 decompress a file called 'file1.bz2' [man]
# bzip2 file1 compress
a file called 'file1' [man]
# gunzip file1.gz decompress
a file called 'file1.gz' [man]
# gzip file1 compress
a file called 'file1' [man]
# gzip -9 file1 compress
with maximum compression [man]
# rar a file1.rar test_file create
an archive rar called 'file1.rar' [man]
# rar a file1.rar file1 file2 dir1 compress 'file1', 'file2' and 'dir1' simultaneously [man]
# rar x file1.rar decompress rar archive [man]
# tar -cvf
archive.tar file1 create a
uncompressed tarball [man]
# tar -cvf
archive.tar file1 file2 dir1 create
an archive containing 'file1', 'file2' and 'dir1' [man]
# tar -tf archive.tar show
contents of an archive [man]
# tar -xvf archive.tar extract
a tarball [man]
# tar -xvf archive.tar -C /tmp extract a tarball into / tmp
[man]
# tar -cvfj archive.tar.bz2 dir1 create a tarball compressed into bzip2 [man]
# tar -xvfj archive.tar.bz2 decompress
a compressed tar archive in bzip2 [man]
# tar -cvfz archive.tar.gz dir1 create a tarball compressed into gzip [man]
# tar -xvfz archive.tar.gz decompress
a compressed tar archive in gzip [man]
# unrar x file1.rar decompress
rar archive [man]
# unzip file1.zip decompress
a zip archive [man]
# zip file1.zip file1 create
an archive compressed in zip [man]
# zip -r file1.zip file1 file2 dir1 compress in zip several files and directories
simultaneously [man]
24. RPM Packages (
Fedora, Red Hat and like):
# rpm -ivh [package.rpm]
install a rpm package [man]
# rpm -ivh --nodeeps [package.rpm] install a rpm package ignoring dependencies requests [man]
# rpm -U [package.rpm] upgrade
a rpm package without changing configuration files [man]
# rpm -F [package.rpm] upgrade
a rpm package only if it is already installed
[man]
# rpm -e [package] remove
a rpm package [man]
# rpm -qa show
all rpm packages installed on the system
[man]
# rpm -qa | grep httpd show
all rpm packages with the name "httpd" [man]
# rpm -qi [package] obtain
information on a specific package installed
[man]
# rpm -qg "System Environment/Daemons" show rpm packages of a group software [man]
# rpm -ql [package] show
list of files provided by a rpm package installed [man]
# rpm -qc [package] show
list of configuration files provided by a rpm package installed [man]
# rpm -q [package] --whatrequires show list of dependencies required for a rpm packet [man]
# rpm -q [package] --whatprovides show capability provided by a rpm package [man]
# rpm -q [package] --scripts show scripts started during installation / removal [man]
# rpm -q [package] --changelog show history of revisions of a rpm package [man]
# rpm -qf /etc/httpd/conf/httpd.conf verify which rpm package belongs to a given file [man]
# rpm -qp [package.rpm] -l show
list of files provided by a rpm package not yet installed [man]
# rpm --import /media/cdrom/RPM-GPG-KEY import public-key digital signature [man]
# rpm --checksig [package.rpm] verify the integrity of a rpm package [man]
# rpm -qa gpg-pubkey verify
integrity of all rpm packages installed
[man]
# rpm -V [package] check
file size, permissions, type, owner, group, MD5 checksum and last
modification [man]
# rpm -Va check
all rpm packages installed on the system - use with caution [man]
# rpm -Vp [package.rpm] verify
a rpm package not yet installed [man]
# rpm -ivh /usr/src/redhat/RPMS/`arch`/[package.rpm] install a package built from a rpm
source [man]
# rpm2cpio [package.rpm] | cpio --extract --make-directories
*bin* extract executable file from a rpm
package [man]
# rpmbuild --rebuild [package.src.rpm] build a rpm package from a rpm
source [man]
25. YUM packages tool (Fedora, RedHat and alike):
# yum -y install [package]
download and install a rpm package [man]
# yum localinstall [package.rpm] That will install an RPM, and try to resolve all the
dependencies for you using your repositories.
[man]
# yum -y update update
all rpm packages installed on the system
[man]
# yum update [package] upgrade
a rpm package [man]
# yum remove [package] remove
a rpm package [man]
# yum list list
all packages installed on the system
[man]
# yum search [package] find
a package on rpm repository [man]
# yum clean [package] clean
up rpm cache erasing downloaded packages
[man]
# yum clean headers remove
all files headers that the system uses to resolve dependency [man]
# yum clean all remove
from the cache packages and headers files
[man]
26. DEB packages (Debian, Ubuntu and like):
# dpkg -i [package.deb]
install / upgrade a deb package [man]
# dpkg -r [package] remove
a deb package from the system [man]
# dpkg -l show
all deb packages installed on the system
[man]
# dpkg -l | grep httpd show
all deb packages with the name "httpd" [man]
# dpkg -s [package] obtain
information on a specific package installed on system [man]
# dpkg -L [package] show
list of files provided by a package installed on system [man]
# dpkg --contents [package.deb] show list of files provided by a package not yet
installed [man]
# dpkg -S /bin/ping verify
which package belongs to a given file
[man]
27. APT packages tool (Debian, Ubuntu and alike):
# apt-cache search [package]
returns list of packages which corresponds
string "searched-packages"
[man]
# apt-cdrom install [package] install / upgrade a deb package from cdrom [man]
# apt-get install [package] install
/ upgrade a deb package [man]
# apt-get update update
the package list [man]
# apt-get upgrade upgrade
all of the installed packages [man]
# apt-get remove [package] remove
a deb package from system [man]
# apt-get check verify
correct resolution of dependencies
[man]
# apt-get clean clean
up cache from packages downloaded [man]
28. View file content:
# cat file1 view the contents of a file starting from the
first row [man]
# head -2 file1 view
first two lines of a file [man]
# less file1 similar
to 'more' command but which allows backward movement in the file as well as
forward movement [man]
# more file1 view
content of a file along [man]
# tac file1 view the contents of a file starting from
the last line [man]
# tail -2 file1 view
last two lines of a file [man]
# tail -f /var/log/messages view
in real time what is added to a file
[man]
29. Text Manipulation:
# cat example.txt | awk 'NR%2==1' remove all even lines from example.txt [man]
# echo a b c | awk '{print $1}' view the first column of a line [man]
# echo a b c | awk '{print $1,$3}' view the first and third column of a line [man]
# cat -n file1 number row of a file [man]
# comm -1 file1 file2 compare
contents of two files by deleting only unique lines from 'file1' [man]
# comm -2 file1 file2 compare
contents of two files by deleting only unique lines from 'file2' [man]
# comm -3 file1 file2 compare
contents of two files by deleting only the lines that appear on both files [man]
# diff file1 file2 find
differences between two files [man]
# grep Aug /var/log/messages look up words "Aug" on file
'/var/log/messages' [man]
# grep ^Aug /var/log/messages look up words that begin with "Aug" on file
'/var/log/messages' [man]
# grep [0-9] /var/log/messages select from file '/var/log/messages' all lines that
contain numbers [man]
# grep Aug -R /var/log/* search
string "Aug" at directory '/var/log' and below [man]
# paste file1 file2 merging
contents of two files for columns [man]
# paste -d '+' file1 file2 merging
contents of two files for columns with '+' delimiter on the center [man]
# sdiff file1 file2 find
differences between two files and merge interactively alike
"diff" [man]
# sed 's/string1/string2/g' example.txt replace "string1" with
"string2" in example.txt
[man]
# sed '/^$/d' example.txt remove
all blank lines from example.txt [man]
# sed '/ *#/d; /^$/d' example.txt remove comments and blank lines from example.txt [man]
# sed -e '1d' exampe.txt eliminates
the first line from file example.txt
[man]
# sed -n '/string1/p' view
only lines that contain the word "string1" [man]
# sed -e 's/ *$//' example.txt remove empty characters at the end of each row [man]
# sed -e 's/string1//g' example.txt remove only the word "string1" from text and leave
intact all [man]
# sed -n '1,5p' example.txt print
from 1th to 5th row of example.txt
[man]
# sed -n '5p;5q' example.txt print row number 5 of example.txt
[man]
# sed -e 's/00*/0/g' example.txt replace more zeros with a single zero [man]
# sort file1 file2 sort
contents of two files [man]
# sort file1 file2 | uniq sort
contents of two files omitting lines repeated
[man]
# sort file1 file2 | uniq -u sort contents of two files by viewing only unique line [man]
# sort file1 file2 | uniq -d sort contents of two files by viewing only duplicate line [man]
# echo 'word' | tr '[:lower:]' '[:upper:]' convert from lower case in upper
case [man]
30. Character set and Format file conversion:
# dos2unix filedos.txt fileunix.txt convert a text file format from MSDOS to
UNIX [man]
# recode ..HTML < page.txt > page.html convert a text file to html [man]
# recode -l | more show
all available formats conversion [man]
# unix2dos fileunix.txt filedos.txt convert a text file format from UNIX to MSDOS [man]
31. Filesystem Analysis:
# badblocks -v /dev/hda1
check bad blocks on disk hda1 [man]
# dosfsck /dev/hda1 repair
/ check integrity of dos filesystems on disk hda1 [man]
# e2fsck /dev/hda1 repair
/ check integrity of ext2 filesystem on disk hda1 [man]
# e2fsck -j /dev/hda1 repair
/ check integrity of ext3 filesystem on disk hda1 [man]
# fsck /dev/hda1 repair
/ check integrity of linux filesystem on disk hda1 [man]
# fsck.ext2 /dev/hda1 repair
/ check integrity of ext2 filesystem on disk hda1 [man]
# fsck.ext3 /dev/hda1 repair
/ check integrity of ext3 filesystem on disk hda1 [man]
# fsck.vfat /dev/hda1 repair
/ check integrity of fat filesystem on disk hda1 [man]
# fsck.msdos /dev/hda1 repair
/ check integrity of dos filesystem on disk hda1 [man]
32. Format a Filesystem:
# fdformat -n /dev/fd0
format a floppy disk [man]
# mke2fs /dev/hda1 create
a filesystem type linux ext2 on hda1 partition
[man]
# mke2fs -j /dev/hda1 create
a filesystem type linux ext3 (journal) on hda1 partition [man]
# mkfs /dev/hda1 create
a filesystem type linux on hda1 partition
[man]
# mkfs -t vfat 32 -F /dev/hda1 create a FAT32 filesystem
[man]
# mkswap /dev/hda3 create
a swap filesystem [man]
33. Filesystem SWAP:
# mkswap /dev/hda3 create a
swap filesystem [man]
# swapon /dev/hda3 activating
a new swap partition [man]
# swapon /dev/hda2 /dev/hdb3 activate two swap partitions [man]
34. Backup:
# find /var/log -name '*.log' | tar cv --files-from=- |
bzip2 > log.tar.bz2 find all files with '.log' extention and make
an bzip archive [man]
# 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 [man]
# 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 [man]
# dd if=/dev/sda of=/tmp/file1 backup content of the harddrive to a file [man]
# dd if=/dev/hda of=/dev/fd0 bs=512 count=1 make a copy of MBR (Master Boot Record)
to floppy [man]
# dd if=/dev/fd0 of=/dev/hda bs=512 count=1 restore MBR from backup copy saved to
floppy [man]
# dump -0aj -f /tmp/home0.bak /home make a full backup of directory '/home' [man]
# dump -1aj -f /tmp/home0.bak /home make a incremental backup of directory '/home' [man]
# restore -if /tmp/home0.bak restoring a backup interactively
[man]
# rsync -rogpav --delete /home /tmp synchronization between directories [man]
# rsync -rogpav -e ssh --delete /home ip_address:/tmp rsync via SSH tunnel [man]
# rsync -az -e ssh --delete ip_addr:/home/public /home/local
synchronize a local directory
with a remote directory via ssh and compression [man]
# rsync -az -e ssh --delete /home/local ip_addr:/home/public
synchronize a remote directory
with a local directory via ssh and compression
[man]
# tar -Puf backup.tar /home/user make a incremental backup of directory '/home/user' [man]
# ( 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 [man]
# ( tar c /home ) | ssh -C user@ip_addr 'cd
/home/backup-home && tar x -p' copy
a local directory on remote directory via ssh
[man]
# tar cf - . | (cd /tmp/backup ; tar xf - ) local copy preserving permits and
links from a directory to another [man]
35. CDROM:
# cd-paranoia -B rip audio tracks from a CD to wav files [man]
# cd-paranoia -- rip
first three audio tracks from a CD to wav files [man]
# cdrecord -v gracetime=2 dev=/dev/cdrom -eject blank=fast
-force clean a rewritable
cdrom [man]
# cdrecord -v dev=/dev/cdrom cd.iso burn an ISO image
[man]
# gzip -dc cd_iso.gz | cdrecord dev=/dev/cdrom - burn a compressed ISO image [man]
# cdrecord --scanbus scan
bus to identify the channel scsi [man]
# dd if=/dev/hdc | md5sum perform
an md5sum on a device, like a CD [man]
# mkisofs /dev/cdrom > cd.iso create an iso image of cdrom on disk [man]
# mkisofs /dev/cdrom | gzip > cd_iso.gz create a compressed iso image of cdrom on
disk [man]
# mkisofs -J -allow-leading-dots -R -V create an iso image of a directory [man]
# mount -o loop cd.iso /mnt/iso mount an ISO image
[man]
36. Networking (LAN / WiFi):
# dhclient eth0 active interface 'eth0' in dhcp mode [man]
# ethtool eth0 show
network statistics of eth0 [man]
# host www.example.com lookup
hostname to resolve name to ip address and viceversa [man]
# hostname show
hostname of system [man]
# ifconfig eth0 show
configuration of an ethernet network card
[man]
# ifconfig eth0 192.168.1.1 netmask 255.255.255.0 configure IP Address [man]
# ifconfig eth0 promisc configure
'eth0' in promiscuous mode to gather packets (sniffing) [man]
# ifdown eth0 disable
an interface 'eth0' [man]
# ifup eth0 activate
an interface 'eth0' [man]
# ip link show show
link status of all network interfaces
[man]
# iwconfig eth1 show
wireless networks [man]
# iwlist scan wifi
scanning to display the wireless connections available [man]
# mii-tool eth0 show
link status of 'eth0' [man]
# netstat -tup show
all active network connections and their PID
[man]
# netstat -tupl show
all network services listening on the system and their PID [man]
# netstat -rn show
routing table alike "route -n"
[man]
# nslookup www.example.com lookup
hostname to resolve name to ip address and viceversa [man]
# route -n show
routing table [man]
# route add -net 0/0 gw IP_Gateway configure default gateway [man]
# 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' [man]
# route del
0/0 gw IP_gateway remove static
route [man]
# echo "1" > /proc/sys/net/ipv4/ip_forward activate ip routing temporarily [man]
# tcpdump tcp port 80 show
all HTTP traffic [man]
# whois www.example.com lookup
on Whois database [man]
37. Microsoft Windows networks (samba)
# mount -t smbfs -o username=user,password=pass //WinClient/share
/mnt/share mount a windows network
share [man]
# nbtscan ip_addr netbios
name resolution [man]
# nmblookup -A ip_addr netbios
name resolution [man]
# smbclient -L ip_addr/hostname show remote shares of a windows host [man]
# smbget -Rr smb://ip_addr/share like wget can download files from a host windows via smb [man]
38. IPTABLES (firewall):
# iptables -t filter -L
show all chains of filtering table [man]
# iptables -t nat -L show
all chains of nat table [man]
# iptables -t filter -F clear
all rules from filtering table [man]
# iptables -t nat -F clear
all rules from table nat [man]
# iptables -t filter -X delete
any chains created by user [man]
# iptables -t filter -A INPUT -p tcp --dport telnet -j
ACCEPT allow telnet connections
to input [man]
# iptables -t filter -A OUTPUT -p tcp --dport http -j DROP block HTTP connections to
output [man]
# iptables -t filter -A FORWARD -p tcp --dport pop3 -j
ACCEPT allow POP3 connections to forward
chain [man]
# iptables -t filter -A INPUT -j LOG --log-prefix Logging on input chain [man]
# iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE configure a PAT (Port Address Traslation) on
eth0 masking outbound packets [man]
# 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 [man]
39. Monitoring and debugging:
# free -m displays status of RAM in megabytes [man]
# kill -9 process_id force
closure of the process and finish it
[man]
# kill -1 process_id force
a process to reload configuration [man]
# last reboot show
history reboot [man]
# lsmod display
kernel loaded [man]
# lsof -p process_id display
a list of files opened by processes [man]
# lsof /home/user1 displays
a list of open files in a given path system
[man]
# ps -eafw displays
linux tasks [man]
# ps -e -o pid,args --forest displays linux tasks in a hierarchical mode [man]
# pstree Shows
a tree system processes [man]
# smartctl -A /dev/hda monitoring
reliability of a hard-disk through SMART
[man]
# smartctl -i /dev/hda check
if SMART is active on a hard-disk [man]
# strace -c ls >/dev/null display system calls made and received by a process [man]
# strace -f -e open ls >/dev/null display library calls
[man]
# tail /var/log/dmesg show
events inherent to the process of booting kernel [man]
# tail /var/log/messages show
system events [man]
# top display linux
tasks using most cpu [man]
# watch -n1 'cat /proc/interrupts' display interrupts in real-time [man]
40. Others useful commands:
# alias hh='history' set
an alias for a command - hh = history
[man]
# apropos ...keyword display
a list of commands that pertain to keywords of a program , useful when you know
what your program does, but you don't know the name of the command [man]
# chsh change shell
command [man]
# chsh --list-shells nice
command to know if you have to remote into another box [man]
# gpg -c file1 encrypt
a file with GNU Privacy Guard [man]
# gpg file1.gpg decrypt
a file with GNU Privacy Guard [man]
# ldd /usr/bin/ssh show
shared libraries required by ssh program
[man]
# man ping display
the on-line manual pages for example on ping command - use '-k' option to find
any related commands [man]
# mkbootdisk --device /dev/fd0 `uname -r` create a boot floppy [man]
# wget -r www.example.com download
an entire web site [man]
# wget -c www.example.com/file.iso download a file with the ability to stop the download and
resume later [man]
# echo 'wget -c www.example.com/files.iso' | at 09:00 start a download at any given time [man]
# whatis ...keyword displays
description of what a program does
[man]
# 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 [man]
Linux has 7 different run levels (or operating modes):
- rc0.d - System Halted
- rc1.d - Single User Mode
- rc2.d - Single User Mode with
Networking
- rc3.d - Multi-User Mode - boot up
in text
mode
- rc4.d - Not yet Defined
- rc5.d - Multi-User Mode -
boot up in X Windows
- rc6.d - Shutdown & Reboot
