Linux Commands Line - v1.0：http://www.linuxguide.it/linux_commands_line_en.htm
├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
├Shutdown, Restart of a system and Logout
│├shutdown -h now
││└shutdown system
│├init 0
││└shutdown system
│├shutdown -r hours:minutes &
││└planned shutdown of the system
│├shutdown -c
││└cancel a planned shutdown of the system
│├shutdown -r now
││└reboot
│├reboot
││└reboot
│└logout
│ └leaving session
├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)
├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
├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
├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)
├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
│└alias hh='history'
│ └set an alias for a command - hh = history
├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
├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
├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
├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
├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
├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
├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
├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
├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
├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
├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
├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
├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
├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
├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
├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
├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
├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
├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
└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