Command Code | Notes |
---|---|
arch | Display the processor architecture of the machine (1) |
uname -m | Display the processor architecture of the machine (2) |
uname -r | Display the kernel version in use |
dmidecode -q | Displays hardware system components -(SMBIOS / DMI) |
hdparm -i /dev/hda | List the architectural characteristics of a disk |
hdparm -tT /dev/sda | Perform a test read operation on a disk |
cat /proc/cpuinfo | Display information about CPU info |
cat /proc/interrupts | Display interrupts |
cat /proc/meminfo | Verify memory usage |
cat /proc/swaps | Shows which swaps are being used |
cat /proc/version | Show kernel version |
cat /proc/net/dev | Show network adapters and statistics |
cat /proc/mounts | Show loaded filesystems |
lspci -tv | List PCI devices |
lsusb -tv | Show USB devices |
date | Show system date |
cal 2007 | Show Calendar 2007 |
date 041217002007.00 | Setting the Date and Time - Month Day Hour Minute Year. Seconds |
clock -w | Save time changes to BIOS |
Command Code | Explanation |
---|---|
shutdown -h now | Shutdown System |
init 0 | Shut down the system |
telinit 0 | Shut down the system |
shutdown -h hours:minutes & | Shuts down the system at a predetermined time |
shutdown -c | Cancel scheduled system shutdown |
shutdown -r now | Reboot |
reboot | Reboot |
logout | Logout |
Command Code | Comment Description |
---|---|
cd /home | Enter'/ home' directory' |
cd .. | Return to the previous directory |
cd ../.. | Returns to the previous two levels of directories |
cd | Go to Personal Master Catalog |
cd ~user1 | Go to your personal home directory |
cd - | Return to the last directory |
pwd | Displaying the working path |
ls | Viewing files in a directory |
ls -F | Viewing files in a directory |
ls -l | Show file and directory details |
ls -a | Show hidden files |
ls *[0-9]* | Display file and directory names containing numbers |
tree | Displaying the tree structure of files and directories starting from the root directory |
lstree | Displaying the tree structure of files and directories starting from the root directory |
mkdir dir1 | Creates a directory called'dir1' directory' |
mkdir dir1 dir2 | Creates two directories at the same time |
mkdir -p /tmp/dir1/dir2 | Creating a directory tree |
rm -f file1 | Delete a file called'file1' file' |
rmdir dir1 | Delete a directory called'dir1' in a directory called' |
rm -rf dir1 | Delete a directory called'dir1' and delete its contents at the same time |
rm -rf dir1 dir2 | Delete two directories and their contents at the same time |
mv dir1 new_dir | Rename/move a directory |
cp file1 file2 | Copying a file |
cp dir0/g' example.txt | Replace multiple zeros with a single zero |
cat -n file1 | Marks the number of lines in a file |
cat example.txt | awk 'NR%2==1' | Delete all even lines in example.txt file |
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 columns of a line |
paste file1 file2 | Merge the contents of two files or two columns |
paste -d '+' file1 file2 | Merge the contents of two files or two columns, separating them with the"+" Sort |
sort file1 file2 | Sort the contents of two files |
sort file1 file2 | uniq | Take out the union of two files( Keep only one copy of duplicate lines) |
sort file1 file2 | uniq -u | Delete the intersection and leave the rest of the rows. |
sort file1 file2 | uniq -d | Remove the intersection of two files( Leave only the files that exist in both files.) |
comm -1 file1 file2 | Compare the contents of two files and remove only'file1' Removes only the contents of the two files. |
comm -2 file1 file2 | Compare the contents of two files and remove only'file2' Included content |
comm -3 file1 file2 | Comparing the contents of two files removes only the parts that are common to both files. |
Command Code | Explanation |
---|---|
dos2unix filedos.txt fileunix.txt | Converts the format of a text file from MSDOS to UNIX. |
unix2dos fileunix.txt filedos.txt | Converts a text file from UNIX to MSDOS. |
recode ..HTML < page.txt > page.html | Convert a text file to html |
recode -l | more | Show all allowed conversion formats |
Command Code | Explanation |
---|---|
badblocks -v /dev/hda1 | Check for bad blocks on disk hda1 |
fsck /dev/hda1 | Repair/check integrity of linux file system on disk hda1 |
fsck.ext2 /dev/hda1 | Repair/check integrity of ext2 file system on disk hda1 |
e2fsck /dev/hda1 | Repair/check integrity of ext2 file system on disk hda1 |
e2fsck -j /dev/hda1 | Repair/check the integrity of the ext3 file system on disk hda1 |
fsck.ext3 /dev/hda1 | Repair/check the integrity of the ext3 file system on disk hda1 |
fsck.vfat /dev/hda1 | Repair/check the integrity of the fat file system on disk hda1 |
fsck.msdos /dev/hda1 | Repair/check the integrity of the dos file system on disk hda1 |
dosfsck /dev/hda1 | Repair/check the integrity of the dos file system on disk hda1 |
Command Code | Comment Explanation |
---|---|
mkfs /dev/hda1 | Creates a file system on the hda1 partition. |
mke2fs /dev/hda1 | Create a linux ext2 file system on hda1 partition |
mke2fs -j /dev/hda1 | Create a linux ext3 on partition hda1( logging) file system on the hda1 partition |
mkfs -t vfat 32 -F /dev/hda1 | Create a FAT32 file system |
fdformat -n /dev/fd0 | Format a floppy disk |
mkswap /dev/hda3 | Creating a swap filesystem |
Command Code | Explanation |
---|---|
mkswap /dev/hda3 | Creates a swap file system |
swapon /dev/hda3 | Enables a new swap file system |
swapon /dev/hda2 /dev/hdb3 | Enable two swap partitions |
Command Code | Note Explanation |
---|---|
dump -0aj -f /tmp/home0.bak /home | Makes a'/home' full backup of the directory |
dump -1aj -f /tmp/home0.bak /home | Makes an interactive backup of a'/home' interactive backup of a catalog |
restore -if /tmp/home0.bak | Restore an interactive backup |
rsync -rogpav --delete /home /tmp | Synchronize both directories |
rsync -rogpav -e ssh --delete /home ip_address:/tmp | rsync over an SSH channel |
rsync -az -e ssh --delete ip_addr:/home/public /home/local | Synchronize a remote directory to a local directory via ssh and compression |
rsync -az -e ssh --delete /home/local ip_addr:/home/public | Synchronize a local directory to a remote directory via ssh and compression |
dd bs=1M if=/dev/hda | gzip | ssh user@ip_addr 'dd of=hda.gz' | Perform a backup of a local disk on a remote host via ssh |
dd if=/dev/sda of=/tmp/file1 | Backup disk contents to a file |
tar -Puf backup.tar /home/user | Perform an interactive backup operation of the'/home/user' directory interactively |
( cd /tmp/local/ && tar c . ) | ssh -C user@ip_addr 'cd /home/share/ && tar x -p' | Copying the contents of a directory to a remote directory via ssh |
( tar c /home ) | ssh -C user@ip_addr 'cd /home/backup-home && tar x -p' | Copy a local directory to a remote directory via ssh |
tar cf - . | (cd /tmp/backup ; tar xf - ) | Locally copy a directory to another location, preserving permissions and links. |
find /home/user1 -name '*.txt' | xargs cp -av --target-directory=/home/backup/ --parents | Find and copy all files ending with'.txt' endings to another directory |
find /var/log -name '*.log' | tar cv --files-from=- | bzip2 > log.tar.bz2 | Finds all files ending in'.log' endings and make a bzip package. |
dd if=/dev/hda of=/dev/fd0 bs=512 count=1 | Do a copy of the MBR(Master Boot Record) contents to a floppy disk |
dd if=/dev/fd0 of=/dev/hda bs=512 count=1 | Restore MBR contents from a backup that has been saved to a floppy diskette |
Command Code | Comment Explanation |
---|---|
cdrecord -v gracetime=2 dev=/dev/cdrom -eject blank=fast -force | Empties the contents of a rewritable CD-ROM |
mkisofs /dev/cdrom > cd.iso | Creates a CD-ROM iso image file on a disk. |
mkisofs /dev/cdrom | gzip > cd_iso.gz | Creates a compressed CD-ROM iso image on disk. |
mkisofs -J -allow-leading-dots -R -V "Label CD" -iso-level 4 -o ./cd.iso data_cd | Creates an iso image of a directory. |
cdrecord -v dev=/dev/cdrom cd.iso | Burn an ISO image file |
gzip -dc cd_iso.gz | cdrecord dev=/dev/cdrom - | Burn a compressed ISO image file |
mount -o loop cd.iso /mnt/iso | Mount an ISO image file |
cd-paranoia -B | Transcribe audio tracks from a CD-ROM to a wav file |
cd-paranoia -- "-3" | Transcribe tracks from a CD-ROM to a wav file (parameter -3) |
cdrecord --scanbus | Scan the bus to recognize scsi channels |
dd if=/dev/hdc | md5sum | Verify the md5sum encoding of a device, e.g. a CD-ROM. |
Command code | Notes |
---|---|
dhclient eth0 | Enables the 'eth0' network device in dhcp mode. |
ethtool eth0 | Display traffic statistics for network card 'eth0'. |
host www.example.com | Find hostnames to resolve names to IP addresses and mirrors |
hostname | Display hostnames |
ifconfig eth0 | Display the configuration of an Ethernet card |
ifconfig eth0 192.168.1.1 netmask 255.255.255.0 | Controlling IP Addresses |
ifconfig eth0 promisc | Set 'eth0' to promiscuous mode for packet sniffing |
ifdown eth0 | Disabling an 'eth0' network device |
ifup eth0 | Enable an 'eth0' network device |
ip link show | Display the connection status of all network devices |
iwconfig eth1 | Display the configuration of a wireless card |
iwlist scan | Show wireless networks |
mii-tool eth0 | Display the connection status of 'eth0'. |
netstat -tup | Show all enabled network connections and their PIDs |
netstat -tup1 | Show all listening network services on the system and their PIDs. |
netstat -rn | Display the routing table, similar to the "route -n" command. |
nslookup www.example.com | Finds hostnames to resolve names and IP addresses and mirrors them. |
route -n | Display the routing table |
route add -net 0/0 gw IP Gateway | Controlling Predefined Gateways |
route add -net 192.168.0.0 netmask 255.255.0.0 gw 192.168.1.1 | Controls static routes to network '192.168.0.0/16'. |
route del 0/0 gw IP gateway | Delete static routes |
echo “1”> /proc/sys/net/ipv4/ip_foward | Activate IP Forwarding |
tcpdump tcp port 80 | Show all HTTP loops |
whois www.example.com | Lookup in Whois database |
Command Code | Note Explanation |
---|---|
mount -t smbfs -o username=user,password=pass | Mount a windows network share |
nbtscan ip addr | netbios name resolution |
nmblookup -A ip addr | netbios name resolution |
smbclient -L ip addr/hostname | Show remote share of a windows host |
smbget -Rr smb: | Download files from a windows host via smb like wget. |
Command Code | Explanation |
---|---|
iptables -t filter -L | Displays all links in the filter table |
iptables -t nae -L | Displays all links in the nat table |
iptables -t filter -F | Clears all rules based on the filter table |
iptables -t nat -F | Clears all rules based on the nat table |
iptables -t filter -X | Delete all links created by the user |
iptables -t filter -A INPUT -p tcp --dport telnet -j ACCEPT | Allow telnet access |
iptables -t filter -A OUTPUT -p tcp --dport telnet -j DROP | Block telnet access |
iptables -t filter -A FORWARD -p tcp --dport pop3 -j ACCEPT | Allow forwarding of POP3 connections on links |
iptables -t filter -A INPUT -j LOG --log-prefix | Log all packets blocked on the link |
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE | Set up a PAT (Port Address Translation) to mask outgoing packets at eth0 |
iptables -t nat -A POSTROUTING -d 192.168.0.1 -p tcp -m tcp --dport 22-j DNAT --to-destination 10.0.0.2:22 | Divert packets destined for one host address to other hosts |
Command Code | Notes |
---|---|
free -m | List RAM status in megabytes |
kill -9 process id | Force a process to shut down and end it |
kill -1 process id | Force a process to reload its configuration |
last reboot | Show reboot history |
lsmod | List the status of kernel modules |
lsof -p process id | List a list of files opened by a process |
lsof /home/user1 | List open files in a given system path |
ps -eafw | List linux tasks |
ps -e -o pid,args --forest | List linux tasks in a hierarchical manner |
pstress | Display programs in a tree view |
smartctl -A /dev/hda | Monitor the reliability of hard disk devices by enabling SMART. |
smartctl -i /dev/hda | Check if SMART is enabled for a hard disk device. |
strace -c ls >/dev/null | List system calls made and received by a process |
strace -f -e open ls >/dev/null | List library calls |
tail /var/log/dmesg | Display internal events during kernel boot |
tail /val/log/messages | Show system events |
top | List the linux tasks that use the most CPU resources |
watch -nl ‘cat /proc/interrupts’ | List real-time interrupts |
Command Code | Notes |
---|---|
alias hh='history' | Set an alias for the command history. |
apropos ...keyword | Make a list of commands with program keywords, especially useful if you only know what the program does and you don't remember the commands. |
chsh | Changing shell commands |
chsh --list-shells | A nice command to know if you have to connect remotely to another machine. |
gpg -c filel | Encrypt a file with GNU Privacy Guard |
gpg filel.gpg | Decrypt a file with GNU Privacy Guard. |