Linux Commands For Developers

[root]

1. HARDWARE INFORMATION

#Display messages in kernel ring buffer
dmesg

#Display CPU information.
cat /proc/cpuinfo

#Display memory information.
cat /proc/meminfo

#Display free and used memory ( -h for human readable, -m for MB, -g for GB.).
free -h

#Display PCI devices.
lspci -tv

#Display USB devices.
lsusb -tv

#Display DMI/SMBIOS (hardware info) from the BIOS.
dmidecode

#Show info about disk sda.
hdparm -i /dev/sda

#Perform a read speed test on disk sda.
hdparm -tT /dev/sda

#Test for unreadable blocks on disk sda.
badblocks -s /dev/sda

2. SYSTEM INFORMATION

#Display Linux system information.
uname -a

#Display kernel release information.
uname -r

#Show which version of redhat installed.
cat /etc/redhat-release

#Show how long the system has been running + load.
uptime

#Show system host name.
hostname

#Display the IP addresses of the host.
hostname -I

#Show system reboot history.
last reboot

#Show the current date and time.
date

#Show this month's calendar.
cal

#Display who is online.
w

#Who you are logged in as
whoami

3. USER INFORMATION AND MANAGEMENT

#Display the user and group ids of your current user.
id

#Display the last users who have logged onto the system.
last

#Show who is logged into the system.
who

#how who is logged in and what they are doing.
w

#Create a group named "test".
groupadd test

#Create an account named john, with a comment of "John Smith" and create the user's home directory.
useradd -c "John Smith" -m john

#Delete the john account.
userdel john

#Add the john account to the sales group.
usermod -aG sales john

4. FILE AND DIRECTORY COMMANDS

#List all files in a long listing (detailed) format.
ls -al

#Display the present working directory.
pwd

#Create a directory.
mkdir directory

#Remove (delete) file.
rm file

#Remove the directory and its contents recursively.
rm -r directory

#Force removal of file without prompting for confirmation.
rm -f file

#Forcefully remove directory recursively.
rm -rf directory

#Copy file1 to file2.
cp file1 file2

#Copy source_directory recursively to destination. If destination exists, copy source_directory into destination, otherwise create destination with the contents of source_directory.
cp -r source_directory destination

#Rename or move file1 to file2. If file2 is an existing directory, move file1 into directory file2.
mv file1 file2

#Create symbolic link to linkname.
ln -s /path/to/file linkname

#Create an empty file or update the access and modification times of file.
touch file

#View the contents of file.
cat file

#Browse through a text file.
less file

#Display the first 10 lines of file.
head file

#Display the last 10 lines of file.
tail file

#Display the last 10 lines of file and "follow" the file as it grows.
tail -f file

5. FILE PERMISSIONS

PERMISSION EXAMPLE

U   G   W
rwx rwx rwx     chmod 777 filename
rwx rwx r-x     chmod 775 filename
rwx r-x r-x     chmod 755 filename
rw- rw- r--     chmod 664 filename
rw- r-- r--     chmod 644 filename

6. PROCESS MANAGEMENT

#Display your currently running processes.
ps

#Display all the currently running processes on the system.
ps -ef

#Display process information for processname.
ps -ef | grep processname

#Display and manage the top processes.
top

#Interactive process viewer (top alternative).
htop

#Kill process with process ID of pid.
kill pid

#Kill all processes named processname.
killall processname

#Start program in the background.
program &

#Display stopped or background jobs.
bg

#Brings the most recent background job to foreground.
fg

#Brings job n to the foreground.
fg n

7. PERFORMANCE MONITORING AND STATISTICS

#Display and manage the top processes.
top

#Interactive process viewer (top alternative).
htop

#Display processor related statistics.
mpstat 1

#Display virtual memory statistics.
vmstat 1

#Display I/O statistics.
iostat 1

#Display the last 100 syslog messages  (Use /var/log/syslog for Debian based systems.).
tail 100 /var/log/messages

#Capture and display all packets on interface eth0.
tcpdump -i eth0

#Monitor all traffic on port 80 ( HTTP ).
tcpdump -i eth0 'port 80'

#List all open files on the system.
lsof

#List files opened by user.
lsof -u user

#Display free and used memory ( -h for human readable, -m for MB, -g for GB.).
free -h

#Execute "df -h", showing periodic updates.
watch df -h

8. NETWORKING

#Display all network interfaces and ip address.
ifconfig -a

#Display eth0 address and details.
ifconfig eth0

#Query or control network driver and hardware settings.
ethtool eth0

#Send ICMP echo request to host.
ping host

#Display whois information for domain.
whois domain

#Display DNS information for domain.
dig domain

#Reverse lookup of IP_ADDRESS.
dig -x IP_ADDRESS

#Display DNS ip address for domain.
host domain

#Display the network address of the host name.
hostname -i

#Display all local ip addresses.
hostname -I

#Download http://domain.com/file.
wget http://domain.com/file

#Display listening tcp and udp ports and corresponding programs.
netstat -nutlp

9. ARCHIVES (TAR FILES)

#Create tar named archive.tar containing directory.
tar cf archive.tar directory

#Extract the contents from archive.tar.
tar xf archive.tar

#Create a gzip compressed tar file name archive.tar.gz.
tar czf archive.tar.gz directory

#Extract a gzip compressed tar file.
tar xzf archive.tar.gz

#Create a tar file with bzip2 compression.
tar cjf archive.tar.bz2 directory

#Extract a bzip2 compressed tar file.
tar xjf archive.tar.bz2

10. SEARCH

#Search for pattern in file.
grep pattern file

#Search recursively for pattern in directory.
grep -r pattern directory

#Find files and directories by name.
locate name

#Find files in /home/john that start with "prefix".
find /home/john -name 'prefix*'

#Find files larger than 100MB in /home.
find /home -size +100M

11. SSH LOGINS

#Connect to host as your local username.
ssh host

#Connect to host as user.
ssh user@host

#Connect to host using port.
ssh -p port user@host

12. FILE TRANSFERS

#Secure copy file.txt to the /tmp folder on server.
scp file.txt server:/tmp

#Copy *.html files from server to the local /tmp folder.
scp server:/var/www/*.html /tmp

#Copy all files and directories recursively from server to the current system's /tmp folder.
scp -r server:/var/www /tmp

#Synchronize /home to /backups/home.
rsync -a /home /backups/

#Synchronize files/directories between the local and remote system with compression enabled.
rsync -avz /home server:/backups/

13. DISK USAGE

#Show free and used space on mounted filesystems.
df -h

#Show free and used inodes on mounted filesystems.
df -i

#Display disks partitions sizes and types.
fdisk -l

#Display disk usage for all files and directories in human readable format.
du -ah

#Display total disk usage off the current directory.
du -sh

14. DIRECTORY NAVIGATION

#To go up one level of the directory tree.  (Change into the parent directory.).
cd ..

#Go to the $HOME directory.
cd

#Change to the /etc directory.
cd /etc

@Linux-Help

[root]

Installing packages commands posting soon.

[Danuva]

Thanks <3

[root]

@Danuva welcome bro

[fern]

nice post :hearts:

[dinlinux]

Great work. 👍Hope to see more from you.

[root]

@dinlinux Yah, i'll post everything about linux

[isuru mahesh perera]

thanx <3