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On this page, you will find Basic Linux Commands and important ones in the title of Linux Cheat Sheet Commands. As you know Linux is widely used in Networking World. Network Engineers and System Administrators use these important operating system commands a lot in their daily routine or critical operational activities.
System Information Commands
File Commands
ls Options
Process Management Commands
Networking Commands
Help Commands
User Information Commands
File Permissions
Search Commands
File Transfer Commands
Disk Usage Commands
Compress and Decompress Commands
Install Commands
Hardware Information Commands
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System Information Commands
uname -a | shows Linux system info |
uname -r | shows kernel release info |
cat /etc/redhat-release | shows installed RedHat version |
uptime | displays system running/lifetime |
hostname | shows system hostname |
hostname -I | shows IP addresses of the host |
last reboot | displays system reboot history |
date | displays current date and time |
cal | displays monthly calendar |
mount | shows mounted filesystems |
File Commands
ls -l | shows file type and access permission |
ls -a | lists also hidden files |
ls -al | lists files and directories detailly |
pwd | shows present directory |
mkdir directory | creates a directory |
rm xyz | deletes file xyz |
rm -r /xyz | deletes directory /xyz and its contents recursively |
rm -f abc | forcefully deletes abc file without confirmation |
rm -rf /xyz | forcefully deletes directory /xyz recursively |
cp aaa bbb | copies aaa file to bbb file |
cp -r /xxx /yyy | copies /xxx directıry to /yyy directory |
mv aaa bbb | renames or moves file aaa to file bbb |
touch abc | creates an empty file named abc |
cat abc | used to view file abc |
less abc | browse through a text file abc |
head abc | displays first 10 lines of file abc |
tail abc | displays last 10 lines of file abc |
tail -f abc | displays last 10 lines of file abc and follow it as it grows |
tail -F abc | outputs last lines of abc as it changes |
file abc | gets type of abc |
gpg -c abc | encrypts file abc |
gpg abc | decrypts file abc |
gpg abc | decrypts file abc |
gpg abc | decrypts file abc |
dir | shows files in the current directory |
put abc | uploads file ‘abc’ from local to the remote device |
get file | downloads file ‘abc’ from remote to local device |
ls Options
-a | shows all (including hidden) |
-R | recursive list |
-r | reverse order |
-t | sort by last modified |
-S | sort by file size |
-l | long listing format |
-1 | one file per line |
-m | comma-separated output |
-Q | quoted output |
Process Management Commands
ps | displays currently running processes |
ps PID | gives the status of a particular process |
pidof | gives the process ID of a process |
ps -ef | displays all running processes on the system |
ps -ef | grep xyz | displays process information for xyz |
top | displays and manages the top processes |
htop | interactive process viewer (top alternative) |
kill pid | kills the process with the process ID of pid |
pkill xyz | kills the process with name xyz |
killall abc | kills all processes named abc |
program & | starts a program in the background |
bg | lists and resumes stopped jobs in the background |
fg | brings the most recent background job to the foreground. |
fg x | brings job x to the foreground |
nice | starts a process with a given priority |
renice | changes priority of an already running process |
pstree | displays processes in a tree-like diagram |
pmap | displays a memory usage map of processes |
lsof | lists files opened by running processes |
Networking Commands
arp | displays ARP table of the device |
arpwatch | displays ethernet activity and Ethernet/ip pairings |
bmon | displays bandwidth, captures |
curl | used for file transfer |
dhclient | used to analyze clients IP address, subnet mask, gateway, DNS server |
dig | used for simple DNS lookup |
dstat | collects and shows system resources |
ethtool | used to check settings of your NIC |
ftp | used for file transfer |
host | used for IP-Name matchings |
hping3 | used for packet analyze |
ifstat | used to monitor network interface statistics |
ip addr | used to check network interfaces and routing activities |
iptables | used for IP packet filtering |
iftop | displays current bandwidth usage |
ifup/ifdown | used to enable or disable interfaces |
iwconfig | used to configure wireless interfaces |
netstat | to check network connections |
nload | used as a bandwidth monitoring tool |
nmap | used for security audits |
nslookup | used also for DNS query |
ping | used to check reachability |
route | displays IP Routing Table |
scp | secured file transfer |
sftp | secured file transfer |
ss | gives detailed information about the sockets |
ssh | used for secure connection |
tshark | analyzing and capturing |
tcpdump | used for analyzing and capturing |
telnet | used for classical non-secure connection |
tshark | used for packet analyze |
tracepath | used for path tracking |
traceroute | used for path tracking |
w | used to check the current system activity |
wget | used to download the content of the web servers |
whois | checks the whois database and return with IP and Domain info |
Help Commands
command -h / command –help | to review all available options of the “command” |
info command | to find info documents about the “command” |
whatis command | displays a single line description about the ”command” |
$ man UNIXCOMMAND | to view a detailed man page of the “command” |
apropos | used to search man pages for available commands on specific functionality. |
User Information Commands
id | shows user&group ids of the current user |
last | shows the last users logged on |
whoami | shows who you are logged in as |
who | shows who is logged into the system |
w | shows who is logged in and what they do |
groupadd test | creates group “test” |
useradd -c “AS” -m Andy | creates “Andy” account with comment “AS” |
userdel Andy | deletes account “Andy” |
usermod -aG Staff Andy | adds account “Andy” to the “Staff” group |
File Permissions
chown user | changes ownership of a file/directory |
chown user:group filename | changes user and group for a file or directory |
File Permissions | r (read) permission, 4 w (write) permission, 2 x (execute) permission, 1 -= no permission |
File Owner | owner/group/everyone |
File Permissions Examples | 777 | Owner, Group, Everyone has rwx permissions 744 | Owner has rwx permission, Group, Everyone has r permission 755 | Owner has rwx permission, Group, Everyone has rx permissions 776 | Owner, Group has rwx permission, Everyone has rw permissions |
Search Commands
grep x file | searches for x in a file |
grep -i | case insensitive search |
grep -r | recursive search |
grep -v | inverted search |
grep -o | shows only matched part of the file |
find /dir/ -name aaa* | finds files starting with aaa in dir |
find /dir/ -user Andy | finds files owned by Andy in dir |
find /dir/ -mmin 10 | finds files modified less than 10 minutes ago in dir |
find /home -size +500M | finds files larger than 500MB in /xyz |
find [/folder/location] -name [x] | finds file names starting with character x |
whereis aaa | locates the binary, source, and manual page of aaa |
locate abc | finds the location of abc quickly |
File Transfer Commands
scp file.txt server:/tmp | secure copy file.txt to the /tmp folder on server |
scp server:/var/www/*.html /tmp | secure copy *.html files in /var/www/ directory on server to the local /tmp folder |
scp -r server:/var/www /tmp | secure copy all files and directories recursively from server to the current system’s /tmp folder. |
rsync -a /home /backups/ | synchronize /home to /backups/ |
rsync -avz /home server:/backups/ | Synchronize files/directories between the local and remote system with compression enabled |
Disk Usage Commands
df | shows free hard disk space on the system |
df -h | shows free and used space on mounted filesystems |
df -i | shows free and used inodes on mounted filesystems |
fdisk -l | shows free and used inodes on mounted filesystems |
du -sh | shows total disk usage off the current directory |
du -ah | shows disk usage for all files and directories in a readable format |
free | shows free RAM on the system |
free -h | shows free and used memory |
findmnt | shows target mount point for all filesystem |
mount /xyz /abc | mounts a device in /xyz to /abc |
Compress and Decompress Commands
gzip abc | compresses abc file using gzip. |
bzip2 abc | compresses abc file using bzip2. |
zip abc.zip abc | compresses abc file into the archive abc.zip. |
tar -czvf archive.tar.gz /home/temp2/ | compresses a full directory with all subdirectories |
gzip -d xyz.gz | extracts xyz.gz with gzip utility |
gunzip xyz.gz | extracts xyz.gz with gzip utility |
bzip2 -d file.php.bz2 | extracts xyz.gz with bzip2 utility |
bunzip2 file.php.bz2 | extracts xyz.gz with bzip2 utility |
unzip xyz.zip | extracts xyz.zip with zip utility |
gunzip -c output.txt.gz | to view the contents of both files without extracting |
tar cf archive.tar directory | creates tar named archive.tar containing directory |
tar xf archive.tar | extracts the contents from archive.tar |
tar czf archive.tar.gz directory | creates a gzip-compressed tar file name archive.tar.gz |
tar xzf archive.tar.gz | extracts a gzip-compressed tar file |
tar cjf archive.tar.bz2 directory | creates a tar file with bzip2 compression |
tar xjf archive.tar.bz2 | extracts a bzip2 compressed tar file |
Install Commands
yum search keyword | compresses abc file using gzip. |
yum install abc | installs abc package |
yum info abc | displays description and summary info about abc package |
rpm -i abc.rpm | installs a package from a local file named abc.rpm |
yum remove abc | Remove/uninstall abc package |
yum list installedl | lists all installed packages with yum |
yum search [keyword] | finds a package by a related keyword |
yum info [package_name] | shows package information and summary |
yum install [package_name.rpm] | installs a package using the YUM package manager |
dnf install [package_name.rpm] | installs a package using the DNF package manager |
apt-get install [package_name] | installs a package using the APT package manager |
rpm -i [package_name.rpm] | installs a .rpm package from a local file |
rpm -e [package_name.rpm] | removes a .rpm package |
Hardware Information Commands
dmesg | displays messages in the kernel ring buffer |
cat /proc/cpuinfo | displays CPU information |
cat /proc/meminfo | displays memory information |
lspci -tv | displays PCI devices |
lsusb -tv | displays USB devices |
dmidecode | displays DMI/SMBIOS from BIOS |
hdparm -i /dev/sda | displays info about disk sda |
hdparm -tT /dev/sda | performs a read speed test on disk sda |
badblocks -s /dev/sda | tests for unreadable blocks on disk sda |
If you find this page useful for your Linux works and if you like it, kindly share this page with your friends, with your colleagues, with your social media followers, etc.
Do not forget, knowledge increases by sharing
