COMMAND
|
DESCRIPTION
|
|
System information
|
arch
|
show architecture of machine
|
uname -r
|
show used kernel version
|
dmidecode -q
|
show hardware system components - (SMBIOS / DMI)
|
hdaparm -i /dev/hda
|
displays the characteristics of a hard-disk
|
hdparm -tT /dev/sda
|
perform test reading on a hard-disk
|
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)
|
lspci -tv
|
display PCI devices
|
lsusb -tv
|
show USB devices
|
date
|
show system date
|
cal 2007
|
show the timetable of 2007
|
date 041217002007.00
|
set date and time - MonthDayhoursMinutesYear.Seconds
|
clock -w
|
save date changes on BIOS
|
linux commands line v1.1 - LinuxGuide.it
|
Shutdown, Restart of a system and Logout
|
shutdown -h now
|
shutdown system
|
init 0
|
telinit 0
|
shutdown -r hours:minutes &
|
planned shutdown of the system
|
shutdown -c
|
cancel a planned shutdown of the system
|
shutdown -r now
|
reboot
|
reboot
|
logout
|
leaving session
|
linux commands line v1.1 - LinuxGuide.it
|
Files and Directory
|
cd /home
|
enter to directory '/ home'
|
cd ..
|
go back one level
|
cd ../..
|
go back two levels
|
cd
|
go to home directory
|
cd ~utente
|
go to home directory
|
cd -
|
go to previous directory
|
pwd
|
show the path of work directory
|
ls
|
view files of directory
|
ls -F
|
view files of directory
|
ls -l
|
show details of files and directory
|
ls -a
|
show hidden files
|
ls *[0-9]*
|
show files and directory containing numbers
|
lstree
|
show files and directories in a tree starting from root
|
mkdir dir1
|
create a directory called 'dir1'
|
mkdir dir1 dir2
|
create two directories simultaneously
|
mkdir -p /tmp/dir1/dir2
|
create a directory tree
|
rm -f file1
|
delete file called 'file1'
|
rmdir dir1
|
delete directory called 'dir1'
|
rm -rf dir1
|
remove a directory called 'dir1' and contents recursively
|
rm -rf dir1 dir2
|
remove two directories and their contents recursively
|
mv dir1 new_dir
|
rename / move a file or directory
|
cp file1 file2
|
copying a file
|
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
|
copy a directory
|
ln -s file1 lnk1
|
create a symbolic link to file or directory
|
ln file1 lnk1
|
create a physical link to file or directory
|
touch -t 0712250000 fileditest
|
modify timestamp of a file or directory - (YYMMDDhhmm)
|
linux commands line v1.1 - LinuxGuide.it
|
File search
|
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' command
|
whereis halt
|
show location of a binary file, source or man
|
which halt
|
show full path to a binary / executable
|
linux commands line v1.1 - LinuxGuide.it
|
Mounting a Filesystem
|
mount /dev/hda2 /mnt/hda2
|
mount disk called hda2 - verify existence of the directory '/ mnt/hda2'
|
umount /dev/hda2
|
unmount disk called hda2 - exit from mount point '/ mnt/hda2' first
|
fuser -km /mnt/hda2
|
force umount when the device is busy
|
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
|
mount /dev/fd0 /mnt/floppy
|
mount a floppy disk
|
mount /dev/cdrom /mnt/cdrom
|
mount a cdrom / dvdrom
|
mount /dev/hdc /mnt/cdrecorder
|
mount a cdrw / dvdrom
|
mount /dev/hdb /mnt/cdrecorder
|
mount a cdrw / dvdrom
|
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
|
linux commands line v1.1 - LinuxGuide.it
|
Disk Space
|
df -h
|
show list of partitions mounted
|
ls -lSr |more
|
show size of the files and directories ordered by size
|
du -sh dir1
|
estimate space used by directory 'dir1'
|
du -sh * | sort -rn
|
show size of the files and directories sorted 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)
|
dpkg-query -W -f='${Installed-Size;10}\t${Package}\n' | sort -k1,1n
|
show space used by deb packages installed sorted by size (ubuntu, debian and like)
|
linux commands line v1.1 - LinuxGuide.it
|
Users and Groups
|
groupadd group_name
|
create a new group
|
groupdel group_name
|
delete a group
|
groupmod -n new_group_name old_group_name
|
rename a group
|
useradd -c "Nome Cognome" -g admin -d /home/user1 -s /bin/bash user1
|
create a new user belongs "admin" group
|
useradd user1
|
create a new user
|
userdel -r user1
|
delete a user ( '-r' eliminates home directory)
|
usermod -c "User FTP" -g system -d /ftp/user1 -s /bin/nologin user1
|
change user attributes
|
passwd
|
change password
|
passwd user1
|
change a user password (only by root)
|
chage -E 2005-12-31 user1
|
set deadline for user password
|
pwck
|
check correct syntax and file format of '/etc/passwd' and users existence
|
grpck
|
check correct syntax and file format of '/etc/group' and groups existence
|
newgrp group_name
|
log in to a new group to change default group of newly created files
|
linux commands line v1.1 - LinuxGuide.it
|
Permits on File - use "+" to set permissions and "-" to remove
|
ls -lh
|
show permits
|
ls /tmp | pr -T5 -W$COLUMNS
|
divide terminal into 5 columns
|
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
|
chown user1 file1
|
change owner of a file
|
chown user1 -R directory1
|
change user owner of a directory and all the files and directories contained inside
|
chgrp gruppo1 file1
|
change group of files
|
chown user1:gruppo1 file1
|
change user and group ownership of a file
|
find / -perm -u+s
|
view all files on the system with SUID configured
|
chmod u+s /bin/file_eseguibile
|
set SUID bit on a binary file - the user that running that file gets same privileges as owner
|
chmod u-s /bin/file_binario
|
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/comune
|
set STIKY bit on a directory - allows files deletion only to legitimate owners
|
chmod o-t /home/comune
|
disable STIKY bit on a directory
|
linux commands line v1.1 - LinuxGuide.it
|
Special Attributes on file - use "+" to set permissions and "-" to remove
|
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
|
show specials attributes
|
linux commands line v1.1 - LinuxGuide.it
|
Archives and compressed files
|
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
|
decompress rar archive
|
unrar x file1.rar
|
decompress rar archive
|
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
|
extract a tarball
|
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
|
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
|
unzip file1.zip
|
decompress a zip archive
|
linux commands line v1.1 - LinuxGuide.it
|
RPM Packages - Fedora, Red Hat and like
|
rpm -ivh package.rpm
|
install a rpm package
|
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_name.rpm
|
remove a rpm 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_name
|
obtain information on a specific package installed
|
rpm -qg "System Environment/Daemons"
|
show rpm packages of a group software
|
rpm -ql package_name
|
show list of files provided by a rpm package installed
|
rpm -qc package_name
|
show list of configuration files provided by a rpm package installed
|
rpm -q package_name --whatrequires
|
show list of dependencies required for a rpm packet
|
rpm -q package_name --whatprovides
|
show capability provided by a rpm package
|
rpm -q package_name --scripts
|
show scripts started during installation / removal
|
rpm -q package_name --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_name
|
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
|
rpm2cpio package.rpm | cpio --extract --make-directories *bin*
|
extract executable file from a rpm package
|
rpm -ivh /usr/src/redhat/RPMS/`arch`/package.rpm
|
install a package built from a rpm source
|
rpmbuild --rebuild package_name.src.rpm
|
build a rpm package from a rpm source
|
linux commands line v1.1 - LinuxGuide.it
|
YUM packages updater - Fedora, RedHat and like
|
yum install package_name
|
download and install a rpm package
|
yum update
|
update all rpm packages installed on the system
|
yum update package_name
|
upgrade a rpm package
|
yum remove package_name
|
remove a rpm package
|
yum list
|
list all packages installed on the system
|
yum search package_name
|
find a package on rpm repository
|
yum clean packages
|
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
|
linux commands line v1.1 - LinuxGuide.it
|
DEB packages - Debian, Ubuntu and like
|
dpkg -i package.deb
|
install / upgrade a deb package
|
dpkg -r package_name
|
remove a deb package from the system
|
dpkg -l
|
show all deb packages installed on the system
|
dpkg -l | grep httpd
|
show all rpm packages with the name "httpd"
|
dpkg -s package_name
|
obtain information on a specific package installed on system
|
dpkg -L package_name
|
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
|
linux commands line v1.1 - LinuxGuide.it
|
APT packages updater - Debian, Ubuntu e like
|
apt-get install package_name
|
install / upgrade a deb package
|
apt-cdrom install package_name
|
install / upgrade a deb package from cdrom
|
apt-get update
|
update all deb packages installed on system
|
apt-get remove package_name
|
remove a deb package from system
|
apt-get check
|
verify correct resolution of dependencies
|
apt-get clean
|
clean up cache from packages downloaded
|
linux commands line v1.1 - LinuxGuide.it
|
View file content
|
cat file1
|
view the contents of a file starting from the first row
|
tac file1
|
view the contents of a file starting from the last line
|
more file1
|
view content of a file along
|
less file1
|
similar to 'more' command but which allows backward movement in the file as well as forward movement
|
head -2 file1
|
view first two lines of a file
|
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
|
linux commands line v1.1 - LinuxGuide.it
|
Text Manipulation
|
cat file_test | [operation: sed, grep, awk, grep, etc] > result.txt
|
syntax to elaborate the text of a file, and write result to a new file
|
cat file_originale | [operazione: sed, grep, awk, grep, etc] >> result.txt
|
syntax to elaborate the text of a file and append result in existing file
|
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
|
sed 's/stringa1/stringa2/g' example.txt
|
replace "string1" with "string2" in example.txt
|
sed '/^$/d' example.txt
|
remove all blank lines from example.txt
|
sed '/ *#/d; /^$/d' example.txt
|
remove comments and blank lines from example.txt
|
echo 'esempio' | tr '[:lower:]' '[:upper:]'
|
convert from lower case in upper case
|
sed -e '1d' result.txt
|
eliminates the first line from file example.txt
|
sed -n '/stringa1/p'
|
view only lines that contain the word "string1"
|
sed -e 's/ *$//' example.txt
|
remove empty characters at the end of each row
|
sed -e 's/stringa1//g' example.txt
|
remove only the word "string1" from text and leave intact all
|
sed -n '1,5p;5q' example.txt
|
view from 1th to 5th row
|
sed -n '5p;5q' example.txt
|
view row number 5
|
sed -e 's/00*/0/g' example.txt
|
replace more zeros with a single zero
|
cat -n file1
|
number row of a file
|
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
|
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
|
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
|
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
|
linux commands line v1.1 - LinuxGuide.it
|
Character set and Format file conversion
|
dos2unix filedos.txt fileunix.txt
|
convert a text file format from MSDOS to UNIX
|
unix2dos fileunix.txt filedos.txt
|
convert a text file format from UNIX to MSDOS
|
recode ..HTML < page.txt > page.html
|
convert a text file to html
|
recode -l | more
|
show all available formats conversion
|
linux commands line v1.1 - LinuxGuide.it
|
Filesystem Analysis
|
badblocks -v /dev/hda1
|
check bad blocks in 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
|
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.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
|
dosfsck /dev/hda1
|
repair / check integrity of dos filesystems on disk hda1
|
linux commands line v1.1 - LinuxGuide.it
|
Format a Filesystem
|
mkfs /dev/hda1
|
create a filesystem type linux on hda1 partition
|
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 -t vfat 32 -F /dev/hda1
|
create a FAT32 filesystem
|
fdformat -n /dev/fd0
|
format a floppy disk
|
mkswap /dev/hda3
|
create a swap filesystem
|
linux commands line v1.1 - LinuxGuide.it
|
SWAP filesystem
|
mkswap /dev/hda3
|
create a swap filesystem
|
swapon /dev/hda3
|
activating a new swap partition
|
swapon /dev/hda2 /dev/hdb3
|
activate two swap partitions
|
linux commands line v1.1 - LinuxGuide.it
|
Backup
|
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 via SSH tunnel
|
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
|
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
|
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
|
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
|
find /var/log -name '*.log' | tar cv --files-from=- | bzip2 > log.tar.bz2
|
find all files with '.log' extention and make an bzip archive
|
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
|
linux commands line v1.1 - LinuxGuide.it
|
CDROM
|
cdrecord -v gracetime=2 dev=/dev/cdrom -eject blank=fast -force
|
clean a rewritable cdrom
|
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 "Label CD" -iso-level 4 -o ./cd.iso data_cd
|
create an iso image of a directory
|
cdrecord -v dev=/dev/cdrom cd.iso
|
burn an ISO image
|
gzip -dc cd_iso.gz | cdrecord dev=/dev/cdrom -
|
burn a compressed ISO image
|
mount -o loop cd.iso /mnt/iso
|
mount an ISO image
|
cd-paranoia -B
|
rip audio tracks from a CD to wav files
|
cd-paranoia -- "-3"
|
rip first three audio tracks from a CD to wav files
|
cdrecord --scanbus
|
scan bus to identify the channel scsi
|
linux commands line v1.1 - LinuxGuide.it
|
Networking - LAN and WiFi
|
ifconfig eth0
|
show configuration of an ethernet network card
|
ifup eth0
|
activate an interface 'eth0'
|
ifdown eth0
|
disable an interface 'eth0'
|
ifconfig eth0 192.168.1.1 netmask 255.255.255.0
|
configure IP Address
|
ifconfig eth0 promisc
|
configure 'eth0' in promiscuous mode to gather packets (sniffing)
|
dhclient eth0
|
active interface 'eth0' in dhcp mode
|
route -n
|
show routing table
|
route add -net 0/0 gw IP_Gateway
|
configura 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
|
remove static route
|
echo "1" > /proc/sys/net/ipv4/ip_forward
|
activate ip routing
|
hostname
|
show hostname
|
host
|
lookup hostname to resolve name to ip address and viceversa
|
ip link show
|
show link status of all interfaces
|
mii-tool eth0
|
show link status of 'eth0'
|
ethtool eth0
|
show statistics of network card 'eth0'
|
netstat -tup
|
show all active network connections and their PID
|
netstat -tupl
|
show all network services listening on the system and their PID
|
tcpdump tcp port 80
|
show all HTTP traffic
|
iwlist scan
|
show wireless networks
|
iwconfig eth1
|
show configuration of a wireless network card
|
linux commands line v1.1 - LinuxGuide.it
|
Microsoft Windows networks - SAMBA
|
nbtscan ip_addr
|
netbios name resolution
|
nmblookup -A ip_addr
|
netbios name resolution
|
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
|
mount -t smbfs -o username=user,password=pass //winclient/share /mnt/share
|
mount a windows network share
|
linux commands line v1.1 - LinuxGuide.it
|
IPTABLES - firewall
|
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 "DROP INPUT"
|
logging sulla chain di input Logging on chain input
|
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
|
linux commands line v1.1 - LinuxGuide.it
|
Monitoring and debugging
|
top
|
display linux tasks using most cpu
|
ps -eafw
|
displays linux tasks
|
ps -e -o pid,args --forest
|
displays linux tasks in a hierarchical mode
|
pstree
|
mostra un albero dei processi sistema Shows a tree system processes
|
kill -9 ID_Processo
|
force closure of the process and finish it
|
kill -1 ID_Processo
|
force a process to reload configuration
|
lsof -p $$
|
display a list of files opened by processes
|
lsof /home/user1
|
displays a list of open files in a given path system
|
strace -c ls >/dev/null
|
display system calls made and received by a process
|
strace -f -e open ls >/dev/null
|
display library calls
|
watch -n1 'cat /proc/interrupts'
|
display interrupts in real-time
|
last reboot
|
show history reboot
|
lsmod
|
display kernel loaded
|
free -m
|
displays status of RAM in megabytes
|
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
|
tail /var/log/dmesg
|
show events inherent to the process of booting kernel
|
tail /var/log/messages
|
show system events
|
linux commands line v1.1 - LinuxGuide.it
|
Other useful commands
|
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 ping
|
display the on-line manual pages for example on ping command
|
whatis ...keyword
|
displays description of what a program does
|
mkbootdisk --device /dev/fd0 `uname -r`
|
create a boot floppy
|
gpg -c file1
|
encrypt a file with GNU Privacy Guard
|
gpg file1.gpg
|
decrypt a file with GNU Privacy Guard
|
wget -r
|
download an entire web site
|
wget -c /file.iso
|
download a file with the ability to stop the download and resume later
|
echo 'wget -c /files.iso' | at 09:00
|
start a download at any given time
|
ldd ssh
|
show shared libraries required by ssh program
|
alias hh='history'
|
set an alias for a command - hh = history
|