| 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.Secondi |
clock -w
|
save changes on BIOS |
| linux commands line v1.0 - LinuxGuide.it |
| Shutdown, Restart of a system and Logout |
| shutdown -h now |
shutdown system |
| init 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 v1.0 - 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 v1.0 - 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 bynary 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 / -name *.rpm -xdev |
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 v1.0 - 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 v1.0 - 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 v1.0 - 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 v1.0 - 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 v1.0 - 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 v1.0 - 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 v1.0 - 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 v1.0 - 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 v1.0 - 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 v1.0 - 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 v1.0 - 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 v1.0 - 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 |
| grep Aug /var/log/messages |
write result of a search within a file |
| 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 v1.0 - 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 v1.0 - 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 v1.0 - 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 v1.0 - 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 v1.0 - 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 v1.0 - 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 v1.0 - 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 www.linuxguide.it |
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 v1.0 - 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 v1.0 - 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 v1.0 - 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 v1.0 - LinuxGuide.it |
| Other useful commands |
| 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 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 |
| ldd ssh |
show shared libraries required by ssh program |
| alias hh='history' |
set an alias for a command - hh = history |
