Table of Contents
- 1 Introduction
- 2 System Information
- 3 File Permissions
- 4 Hardware Information
- 5 Networking
- 6 Archives and File Compression
- 7 Installing Packages
- 8 Search Commands
- 9 SSH Logins
- 10 File Transfers and Management
- 11 File and Directory Operations
- 12 Disk Utilities and Usage
- 13 Environment Variables
- 14 System Processes Management
- 15 File Editors
- 16 File Utilities
- 17 Performance Monitoring and Statistics
- 18 Conclusion
Introduction
Linux commands are powerful tools that allow users to interact with the operating system and perform various tasks efficiently. Whether you’re a beginner or an experienced Linux user, having a cheat sheet of commonly used commands can be invaluable. In this blog post, we’ll provide you with a handy Linux commands cheat sheet to help you navigate through your Linux journey.
System Information
Linux Commands cheat sheet for System Information. You want to query information about your system.
| Commands | Description | For example |
| whoami | Output the current user using the Linux system | [vagrant@localhost ~]$ whoami vagrant |
| w | who or which systems are online especially | [vagrant@localhost ~]$ w 20:29:06 up 3 min, 1 user, load average: 0.00, 0.00, 0.00 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT vagrant pts/0 10.0.2.2 20:27 2.00s 0.01s 0.00s w |
| cal | Outputs the present month’s calendar. | [vagrant@localhost ~]$ cal September 2021 Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 |
| date | Displaying the current date and time. | [vagrant@localhost ~]$ date Tue Sep 21 20:30:00 +07 2021 |
| last reboot | A useful command of how many times your system restarted. | [vagrant@localhost ~]$ last reboot reboot system boot 3.10.0-1127.el7. Tue Sep 21 20:25 – 20:30 (00:04) reboot system boot 3.10.0-1127.el7. Tue Sep 21 14:42 – 17:26 (02:44) reboot system boot 3.10.0-1127.el7. Sat Sep 18 20:56 – 22:00 (01:03) reboot system boot 3.10.0-1127.el7. Sat Sep 18 14:37 – 22:00 (07:22) wtmp begins Sat Sep 18 14:37:54 2021 |
| hostname -I | Outputs the assigned IP address your system is currently | [vagrant@localhost ~]$ hostname -I 10.0.2.15 192.168.3.4 172.17.0.1 |
| hostname | Outputs your system’s hostname | [vagrant@localhost ~]$ hostname localhost.localdomain |
| uptime | Outputs how long your Linux system has been active | [vagrant@localhost ~]$ uptime 20:31:27 up 5 min, 1 user, load average: 0.00, 0.00, 0.00 |
| lsb_release -a | You can obtain information specific to your Linux distribution. This command displays its Distributor ID, Description, Release, and Codename. | vagrant@vagrant:~$ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 21.04 Release: 21.04 Codename: hirsute |
| uname -r | Outputs the kernel release information | [vagrant@localhost ~]$ uname -r 3.10.0-1127.el7.x86_64 |
| uname -a | Displays basic system information like machine name, etc. | [vagrant@localhost ~]$ uname -a Linux localhost.localdomain 3.10.0-1127.el7.x86_64 #1 SMP Tue Mar 31 23:36:51 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux |
File Permissions
Linux Commands cheat sheet for File Permissions. File permissions in Linux relate to Read (r), Write (w), and Execute (x) privileges.
| Commands | Description | For example |
| ls -l | Outputs the file type and the file permissions | [root@localhost vagrant]# ls -l total 0 -rw-rw-r–. 1 vagrant vagrant 0 Sep 21 20:34 devopsroles.com drwxr-xr-x. 2 vagrant vagrant 6 Sep 13 20:12 share |
| chown user:group file_name | Change The user and group privileges | [root@localhost vagrant]# chown huupv:root devopsroles.com [root@localhost vagrant]# ls -l devopsroles.com -rw-rw-r–. 1 huupv root 0 Sep 21 20:34 devopsroles.com |
| chmod 777 file_name | Everyone access the file | [root@localhost vagrant]# chmod 777 devopsroles.com [root@localhost vagrant]# ls -l devopsroles.com -rwxrwxrwx. 1 huupv root 0 Sep 21 20:34 devopsroles.com |
| chmod 755 file_name | The owner of the file: Read, Write, Execute other users and Group will only have read and executed permissions. | [root@localhost vagrant]# chmod 755 devopsroles.com [root@localhost vagrant]# ls -l devopsroles.com -rwxr-xr-x. 1 huupv root 0 Sep 21 20:34 devopsroles.com |
| chmod 766 file_name | The owner of the file: Read, Write, Execute other users and Group will only have Read and Write permissions. | [root@localhost vagrant]# chmod 766 devopsroles.com [root@localhost vagrant]# ls -l devopsroles.com -rwxrw-rw-. 1 huupv root 0 Sep 21 20:34 devopsroles.com |
| touch -a -t | Useful in creating or modifying a file timestamp. -a = accessed -m = modified -t = timestamp – use [[CC]YY]MMDDhhmm[.ss] time format | [root@localhost vagrant]# touch -a -t 201902090123.30 devopsroles.com [root@localhost vagrant]# stat devopsroles.com File: ‘devopsroles.com’ Size: 0 Blocks: 0 IO Block: 4096 regular empty file Device: 801h/2049d Inode: 5323348 Links: 1 Access: (0766/-rwxrw-rw-) Uid: ( 1001/ huupv) Gid: ( 0/ root) Context: unconfined_u:object_r:user_home_t:s0 Access: 2019-02-09 01:23:30.000000000 +0700 Modify: 2021-09-21 20:34:35.629225064 +0700 Change: 2021-09-21 20:43:41.338885218 +0700 Birth: – |
| chgrp group_name filename | Useful in changing the group permission of a file. | [root@localhost vagrant]# ls -l devopsroles.com -rwxr-xr-x. 1 huupv root 0 Sep 21 20:34 devopsroles.com [root@localhost vagrant]# chgrp vagrant devopsroles.com [root@localhost vagrant]# ls -l devopsroles.com -rwxr-xr-x. 1 huupv vagrant 0 Sep 21 20:34 devopsroles.com |
| chmod -c -R | Assign a file the read, write, and execute permissions. | [root@localhost vagrant]# ls -l devopsroles.com -rwxr-xr-x. 1 huupv vagrant 0 Sep 21 20:34 devopsroles.com [root@localhost vagrant]# chmod -c -R 777 devopsroles.com mode of ‘devopsroles.com’ changed from 0755 (rwxr-xr-x) to 0777 (rwxrwxrwx) [root@localhost vagrant]# ls -l devopsroles.com -rwxrwxrwx. 1 huupv vagrant 0 Sep 21 20:34 devopsroles.com |
Hardware Information
Here are some commonly used commands to gather hardware information in Linux:
| Commands | Description | For example |
| cat /proc/cpuinfo | Outputs CPU information of your machine. | [vagrant@localhost ~]$ cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 167 model name : 11th Gen Intel(R) Core(TM) i7-11700 @ 2.50GHz stepping : 1 cpu MHz : 2496.004 cache size : 16384 KB …… |
| cat /proc/meminfo | Outputs Memory information | [vagrant@localhost ~]$ cat /proc/meminfo MemTotal: 498684 kB MemFree: 131816 kB MemAvailable: 343212 kB Buffers: 2068 kB Cached: 207228 kB SwapCached: 0 kB Active: 107336 kB ….. |
| free -h | Outputs both free and used machine memory info. | [vagrant@localhost ~]$ free -h total used free shared buff/cache available Mem: 486M 134M 128M 4.5M 223M 334M Swap: 2.0G 0B 2.0G |
| lshw | Outputs the system’s hardware configuration information. | [vagrant@localhost ~]$ sudo lshw -short H/W path Device Class Description system VirtualBox/0 bus VirtualBox /0/0 memory 128KiB BIOS /0/1 memory 512MiB System memory /0/2 processor 11th Gen Intel(R) Core(TM) i7-11700 @ 2.50GHz /0/100 bridge 440FX – 82441FX PMC [Natoma] /0/100/1 bridge 82371SB PIIX3 ISA [Natoma/Triton II] /0/100/1.1 scsi0 storage 82371AB/EB/MB PIIX4 IDE /0/100/1.1/0.0.0 /dev/sda disk 42GB VBOX HARDDISK /0/100/1.1/0.0.0/1 volume 39GiB Linux filesystem partition /0/100/2 display VirtualBox Graphics Adapter /0/100/3 eth0 network 82540EM Gigabit Ethernet Controller /0/100/4 generic VirtualBox Guest Service /0/100/5 multimedia 82801AA AC’97 Audio Controller /0/100/7 bridge 82371AB/EB/MB PIIX4 ACPI /0/100/8 eth1 network 82540EM Gigabit Ethernet Controller /0/3 input PnP device PNP0303 /0/4 input PnP device PNP0f03 /1 docker0 network Ethernet interface |
| lsblk | Outputs the system’s block devices information. | [vagrant@localhost ~]$ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 40G 0 disk └─sda1 8:1 0 40G 0 part / |
| lspci -tv | Outputs the system’s PCI devices. | [vagrant@localhost ~]$ lspci -tv -[0000:00]-+-00.0 Intel Corporation 440FX – 82441FX PMC [Natoma] +-01.0 Intel Corporation 82371SB PIIX3 ISA [Natoma/Triton II] +-01.1 Intel Corporation 82371AB/EB/MB PIIX4 IDE +-02.0 InnoTek Systemberatung GmbH VirtualBox Graphics Adapter +-03.0 Intel Corporation 82540EM Gigabit Ethernet Controller +-04.0 InnoTek Systemberatung GmbH VirtualBox Guest Service +-05.0 Intel Corporation 82801AA AC’97 Audio Controller +-07.0 Intel Corporation 82371AB/EB/MB PIIX4 ACPI -08.0 Intel Corporation 82540EM Gigabit Ethernet Controller |
| lsusb -tv | Outputs the system’s USB devices. | |
| dmidecode | Outputs the system’s hardware information on DMI/SMBIOS related to the BIOS. | [vagrant@localhost ~]$ sudo dmidecode dmidecode 3.2 Getting SMBIOS data from sysfs. SMBIOS 2.5 present. 10 structures occupying 450 bytes. Table at 0x000E1000. Handle 0x0000, DMI type 0, 20 bytes BIOS Information Vendor: innotek GmbH Version: VirtualBox Release Date: 12/01/2006 Address: 0xE0000 ….. |
| dmesg | Outputs the kernel ring buffer messages. | [vagrant@localhost ~]$ dmesg [ 0.000000] Initializing cgroup subsys cpuset [ 0.000000] Initializing cgroup subsys cpu [ 0.000000] Initializing cgroup subsys cpuacct [ 0.000000] Linux version 3.10.0-1127.el7.x86_64 (mockbuild@kbuilder.bsys.centos.org) (gcc version 4.8.5 20150623 (Red Hat 4.8.5-39) (GCC) ) #1 SMP Tue Mar 31 23:36:51 UTC 2020 [ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-3.10.0-1127.el7.x86_64 root=UUID=1c419d6c-5064-4a2b-953c-05b2c67edb15 ro no_timer_check console=tty0 console=ttyS0,115200n8 net.ifnames=0 biosdevname=0 elevator=noop crashkernel=auto LANG=en_US.UTF-8 [ 0.000000] e820: BIOS-provided physical RAM map: [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable [ 0.000000] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved …. |
| lscpu | Outputs information about the CPU and processing units. | [vagrant@localhost ~]$ lscpu Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 1 On-line CPU(s) list: 0 Thread(s) per core: 1 Core(s) per socket: 1 Socket(s): 1 NUMA node(s): 1 Vendor ID: GenuineIntel CPU family: 6 ….. |
| lsscsi | Lists out the SCSI/SATA devices like hard drives and optical drives. | [vagrant@localhost ~]$ lsscsi [0:0:0:0] disk ATA VBOX HARDDISK 1.0 /dev/sda |
These commands should help you gather hardware information about your Linux system. By utilizing them, you can gain insights into the components and configurations of your machine.
Networking
Here are some commonly used commands to gather networking information in Linux:
| Commands | Description | For example |
| ping hostname_or_IP | Useful in analyzing the responsiveness of a hostname connected to a network. | [vagrant@localhost ~]$ ping 192.168.3.4 PING 192.168.3.4 (192.168.3.4) 56(84) bytes of data. 64 bytes from 192.168.3.4: icmp_seq=1 ttl=64 time=0.017 ms 64 bytes from 192.168.3.4: icmp_seq=2 ttl=64 time=0.021 ms 64 bytes from 192.168.3.4: icmp_seq=3 ttl=64 time=0.021 ms |
| tcpdump | Used to dump network traffic. | [vagrant@localhost ~]$ sudo tcpdump -i eth0 |
| netstat -r -v | Prints network routing, information, and connections. | [vagrant@localhost ~]$ netstat -r -v Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface default gateway 0.0.0.0 UG 0 0 0 eth0 10.0.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 172.17.0.0 0.0.0.0 255.255.0.0 U 0 0 0 docker0 192.168.3.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1 |
| ip addr show | Outputs network interfaces and their related IP addresses. | |
| ifconfig | Outputs configured network interfaces’ IP addresses. | |
| whois domain_name | Reveals more information regarding an active domain name on the internet. | [vagrant@localhost ~]$ whois devopsroles.com Domain Name: DEVOPSROLES.COM Registry Domain ID: 2245154670_DOMAIN_COM-VRSN …… |
| dig domain_name | Reveals DNS information and configuration regarding an active domain name. | |
| dig -x host | It is applicable when dealing with DNS and will reverse lookup an active domain. | [vagrant@localhost ~]$ dig -x huuphan.com ; <<>> DiG 9.11.4-P2-RedHat-9.11.4-26.P2.el7_9.7 <<>> -x huuphan.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 43438 ;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 512 ;; QUESTION SECTION: ;com.huuphan.in-addr.arpa. IN PTR ;; AUTHORITY SECTION: in-addr.arpa. 3486 IN SOA b.in-addr-servers.arpa. nstld.iana.org. 2021090215 1800 900 604800 3600 ;; Query time: 34 msec ;; SERVER: 10.0.2.3#53(10.0.2.3) ;; WHEN: Wed Sep 22 20:23:37 +07 2021 ;; MSG SIZE rcvd: 121 |
| dig -x IP_address | It will reverse lookup an active IP address. | [vagrant@localhost ~]$ dig -x 172.67.137.70 ; <<>> DiG 9.11.4-P2-RedHat-9.11.4-26.P2.el7_9.7 <<>> -x 172.67.137.70 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 52165 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 512 ;; QUESTION SECTION: ;70.137.67.172.in-addr.arpa. IN PTR ;; AUTHORITY SECTION: 67.172.in-addr.arpa. 1800 IN SOA cruz.ns.cloudflare.com. dns.cloudflare.com. 2034580120 10000 2400 604800 3600 ;; Query time: 41 msec ;; SERVER: 10.0.2.3#53(10.0.2.3) ;; WHEN: Wed Sep 22 20:24:27 +07 2021 ;; MSG SIZE rcvd: 117 |
| host domain_name | It will lookup the IP address of an active domain | [vagrant@localhost ~]$ host huuphan.com huuphan.com has address 104.21.73.16 huuphan.com has address 172.67.137.70 huuphan.com has IPv6 address 2606:4700:3032::6815:4910 huuphan.com has IPv6 address 2606:4700:3031::ac43:8946 huuphan.com mail is handled by 10 aspmx2.googlemail.com. huuphan.com mail is handled by 1 aspmx.l.google.com. huuphan.com mail is handled by 5 alt1.aspmx.l.google.com. huuphan.com mail is handled by 10 aspmx3.googlemail.com. huuphan.com mail is handled by 5 alt2.aspmx.l.google.com. |
| wget file_name | Useful in downloading a file from a specified domain name | wget https://www.huuphan.com/filename.zip |
| ifconfig -a | Outputs all the network interface details | |
| ifconfig eth0 | Outputs eth0 configuration and address details. | |
| ethtool eth0 | Used to manage hardware and network drivers query and control settings | [vagrant@localhost ~]$ ethtool eth0 Settings for eth0: Supported ports: [ TP ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Supported pause frame use: No Supports auto-negotiation: Yes Supported FEC modes: Not reported Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Advertised pause frame use: No Advertised auto-negotiation: Yes Advertised FEC modes: Not reported Speed: 1000Mb/s Duplex: Full Port: Twisted Pair PHYAD: 0 Transceiver: internal Auto-negotiation: on MDI-X: off (auto) Cannot get wake-on-lan settings: Operation not permitted Current message level: 0x00000007 (7) drv probe link Link detected: yes |
These commands should help you gather networking information in Linux, enabling you to troubleshoot network issues, check connections, and analyze network configurations.
Archives and File Compression
Archiving and file compression are common tasks in Linux that help to organize and reduce the size of files. Here are some commonly used commands for archives and file compression:
| Commands | Description | For example |
| tar cvf compressed_file_name.tar file_name # creating tar xvf compressed_file_name.tar file_name # extracting | creating or extracting files with .tar | [vagrant@localhost ~]$ tar cvf share.tar share share/ [vagrant@localhost ~]$ tar xvf share.tar share/ |
| tar czf compressed_file_name.tar.gz | compresses a tar file into a gzip archive. | |
| tar cjf archive.tar.bz2 folder | compresses a tar file inside a bz2 archive. | [vagrant@localhost ~]$ tar cjf archive.tar.bz2 share [vagrant@localhost ~]$ ll total 20 -rw-rw-r–. 1 vagrant vagrant 150 Sep 23 07:51 archive.tar.bz2 |
| tar xjf archive.tar.bz2 | extracts a tar file compressed inside a bz2 archive. | |
| gzip, gunzip, zcat file_name | creating, extracting. or viewing files with .gz extension | |
| uuencode, uudecode | creating or extracting files with .Z extension. | |
| zip, unzip -v | creating or extracting files with .Zip extension. | [vagrant@localhost ~]$ zip -r share.zip share adding: share/ (stored 0%) adding: share/abc.txt (stored 0%) [vagrant@localhost ~]$ ls -l share.zip -rw-rw-r–. 1 vagrant vagrant 316 Sep 23 07:56 share.zip [vagrant@localhost ~]$ unzip -v share.zip Archive: share.zip Length Method Size Cmpr Date Time CRC-32 Name ——– —— ——- —- ———- —– ——– —- 0 Stored 0 0% 09-23-2021 07:50 00000000 share/ 0 Stored 0 0% 09-23-2021 07:50 00000000 share/abc.txt ——– ——- — ——- 0 0 0% 2 files |
| bzip2, bunzip2 | creating or extracting files with .bz2 extension. | |
| rar | creating or extracting files with .rar extension. |
These commands should help you perform file compression, archiving, and extraction tasks in Linux. The specific options may vary depending on the command and the desired operation.
Installing Packages
Installing packages is a fundamental task in Linux for adding new software and libraries to your system. The method of package installation can vary depending on the Linux distribution you are using. Here, I’ll provide an overview of package management tools commonly used in different distributions:
| Commands | Description | For example |
| yum search keyword | Search a package installation based on specific keywords. | [vagrant@localhost ~]$ yum search nginx Loaded plugins: fastestmirror Determining fastest mirrors base: mirror.vietnix.vn epel: mirror.xeonbd.com extras: mirror.vietnix.vn updates: mirror.vietnix.vn =============== N/S matched: nginx ========== collectd-nginx.x86_64 : Nginx plugin for collectd munin-nginx.noarch : NGINX support for Munin resource monitoring nginx-all-modules.noarch : A meta package that installs all available Nginx modules nginx-filesystem.noarch : The basic directory layout for the Nginx serve …… |
| yum install package.rpm | The use of a YUM package manager to install and configure a package. | |
| yum info package | To find more information about a package before optionally proceeding with its installation. | [vagrant@localhost ~]$ yum info nginx Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile base: mirror.vietnix.vn epel: mirror.xeonbd.com extras: mirror.vietnix.vn updates: mirror.vietnix.vn Available Packages Name : nginx Arch : x86_64 Epoch : 1 Version : 1.20.1 Release : 2.el7 Size : 586 k Repo : epel/x86_64 Summary : A high performance web server and reverse proxy server URL : https://nginx.org License : BSD Description : Nginx is a web server and a reverse proxy server for HTTP, SMTP, POP3 and : IMAP protocols, with a strong focus on high concurrency, performance and low : memory usage. |
| rpm -i package.rpm | To install a downloaded RPM package. | |
| yum remove package | To uninstall or remove a Yum package from your system. | |
| tar zxvf sourcecode.tar.gz cd sourcecode ./configure make make install | Command sequence to install a package software that comes as a source code. | |
| dnf install package.rpm | Using the DNF package manager to install package software. | |
| apt install package | Using the APT package manager to install package software. | |
| rpm -e package.rpm | Using the RPM package manager to remove or uninstall an rpm package |
Remember to use the sudo command before installation commands to execute them with administrative privileges.
Search Commands
Searching for files, directories, and text within files is a common task in Linux. Here are some commonly used search commands:
| Commands | Description | For example |
| grep pattern file | To search the contents of a file with a pattern | [vagrant@localhost ~]$ grep devopsroles devopsroles.com welocome devopsroles.com |
| grep -r pattern directory_name | Recursively or repeatedly searches within a specified directory for a defined pattern match. | |
| find /path/to/folder -name match-a | search based on a character match. In this case [ match-a ] | [vagrant@localhost ~]$ find /home/vagrant -name devopsroles.com /home/vagrant/devopsroles.com |
| find /path/to/folder -name ‘prefix*’ | Traces a specified system path for files with a matching prefix. | [vagrant@localhost ~]$ find /home/vagrant -name ‘devops*’ /home/vagrant/devopsroles.com |
These commands should help you search for files, directories, and text within files on your Linux system. You can customize the search criteria based on your specific requirements.
SSH Logins
SSH (Secure Shell) is a widely used protocol for securely accessing remote systems over a network. Monitoring SSH logins can be important for security and auditing purposes. Here’s how you can view SSH login information:
| Commands | Description | For example |
| ssh user_name@hostname | Connects you to a remote machine or server | |
| ssh host | Connects you to a specified host through the default port 22. | |
| ssh -p port user_name@hostname | Connects you to a remote machine or server through a specified port. | |
| telnet hostname | Uses telnet’s default port 23 to connect you to a target hostname, remote machine, or server. |
File Transfers and Management
File transfers and management are common tasks in Linux for organizing, moving, copying, and transferring files between different locations. Here are some commonly used commands for file transfers and management:
| Commands | Description | For example |
| rm -r -f | To remove or delete active files and directories | |
| du -s | Give important information regarding the disk usage (storage space) on your Linux system. | [vagrant@localhost ~]$ du -s /home/vagrant 60 /home/vagrant |
| file -b -i | Helps identify the type of file on your system. | [vagrant@localhost ~]$ file -b -i .env text/plain; charset=us-ascii |
| mv -f -i | Used for moving directories or files to a different system path or location. | |
| grep, egrep, fgrep -i -v | Useful in printing lines with a matching pattern. | |
| scp file.txt server:/tmp | To copy files to a remote server. | |
| scp server:/home/vagrant/*.txt /tmp | to copy files from a remote server to a directory on a local machine. | |
| scp -r server:/home/vagrant /tmp | recursively copy all the files and directories on a remote server’s directory to a target machine directory. | |
| rsync -a /var/www /backups/ | Synchronizes the content of two directories (/var/www and /backups) on the same machine. | |
| rsync -avz /home/vagrant server:/backups/ | synchronizes the content of a folder on a local machine with the content of a folder on a remote server. |
These commands should help you with basic file transfers, copying, moving, renaming, and deleting files and directories in Linux. Remember to use appropriate options and double-check before performing any destructive operations like removing or overwriting files.
File and Directory Operations
Working with files and directories is a common task in Linux. Here are some commonly used commands for file and directory operations:
| Commands | Description |
| ls | list the files and directories under and directory path. |
| pwd | print working directory |
| mkdir dir_name | create a directory with the specified name. |
| rm filename | delete a file with the specified name. |
| rm -rf directory_name | recursively and forcefully delete a directory with the specified name. |
| cp filename1 filename2 | copy filename1 to filename2 |
| cp -r directory1 directory2 | recursively copy the content of directory1 to directory2 |
| mv filename1 filename2 | rename filename1 to filename2 |
| ln -s /path/to/file_name link_name | To create a symbolic link (link_name) to a specified file name (file_name). |
| touch filename | to create a new file |
| more filename | open and display the contents of a specified file. |
| cat filename | open and display the contents of a specified file. |
| cat filename1 >> filename2 | appends or adds the content of filename1 at the bottom of filename2. |
| head filename | Outputs the first ten lines of a specified file name. |
| tail filename | Outputs the last ten lines of a specified file name. |
| gpg -c filename | to encrypt a specified file. |
| gpg filename.gpg | to decrypt a specified file with a .gpg extension. |
| wc filename | Outputs the number of bytes, lines, and words of a specified file name. |
| cd | Takes you to the Home directory |
| cd /target/directory | To change directories to a specific directory name. |
These commands should help you perform common file and directory operations in Linux. Be careful when using commands like “rm” or “rmdir” to avoid accidental deletion of important files or directories.
Disk Utilities and Usage
Monitoring disk usage and managing disk-related tasks are essential in Linux to ensure efficient use of storage space. Here are some commonly used disk utilities and commands for disk management and usage:
| Commands | Description | For example |
| df -h | Display the amount of free space in the file system | [vagrant@localhost ~]$ df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 237M 0 237M 0% /dev tmpfs 244M 0 244M 0% /dev/shm tmpfs 244M 4.5M 240M 2% /run tmpfs 244M 0 244M 0% /sys/fs/cgroup /dev/sda1 40G 4.2G 36G 11% / tmpfs 49M 0 49M 0% /run/user/1000 |
| df -i | Works with mounted systems to reveal their free inodes. | [vagrant@localhost ~]$ df -i Filesystem Inodes IUsed IFree IUse% Mounted on devtmpfs 60456 306 60150 1% /dev tmpfs 62335 1 62334 1% /dev/shm tmpfs 62335 395 61940 1% /run tmpfs 62335 16 62319 1% /sys/fs/cgroup /dev/sda1 20971008 48415 20922593 1% / tmpfs 62335 1 62334 1% /run/user/1000 |
| fdisk -l | print partition tables of all devices | [vagrant@localhost ~]$ sudo fdisk -l Disk /dev/sda: 42.9 GB, 42949672960 bytes, 83886080 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk label type: dos Disk identifier: 0x0009ef1a Device Boot Start End Blocks Id System /dev/sda1 * 2048 83886079 41942016 83 Linux |
| du -ah | Outputs files and directories disk usage. | [vagrant@localhost ~]$ du -ah 4.0K ./.bash_logout 4.0K ./.bash_profile 4.0K ./.bashrc 4.0K ./.ssh/authorized_keys 4.0K ./.ssh/known_hosts 8.0K ./.ssh 0 ./share 4.0K ./.env 8.0K ./.bash_history 4.0K ./devopsroles.com 4.0K ./myscript_onLocal.sh 12K ./share.tar 4.0K ./archive.tar.bz2 4.0K ./share.zip 4.0K ./linuxopratingsystem.net 4.0K ./.viminfo 68K . |
| findmnt | Outputs the target mount point associated with all your file systems. | |
| mount device_path mount_point | to mount a device. | |
| mkfs -t -V | to create a new file system. | |
| resize2fs | updating a file system, especially after lvextend* | |
| fsck -A -N | to check and repair a file system. | |
| pvcreate | creating a physical volume. | |
| mount -a -t | mounting a file system. | |
| lvcreate | creating a logical volume. | |
| unmount -f -v | unmounting a mounted file system. |
These commands and utilities will help you monitor disk usage, manage partitions, mount file systems, and perform disk-related tasks in Linux. Make sure to use appropriate administrative privileges, such as “sudo,” when required.
Environment Variables
| Commands | Description | For example |
| env | Display all exported environment or run a program in a modified environment | vagrant@devopsroles:~$ env SHELL=/bin/bash PWD=/home/vagrant LOGNAME=vagrant XDG_SESSION_TYPE=tty MOTD_SHOWN=pam HOME=/home/vagrant LANG=en_US.UTF-8 ….. |
| variable_name=variable_value | to assign a variable name with a variable value. | vagrant@devopsroles:~$ site=devopsroles.com vagrant@devopsroles:~$ echo $site devopsroles.com |
| echo $Variable_name | Outputs the value of a defined variable on the terminal. | vagrant@devopsroles:~$ echo $site devopsroles.com |
| export Variable = value | To assign an environment variable a new value. | vagrant@devopsroles:~$ export site=devopsroles.com vagrant@devopsroles:~$ env | grep site site=devopsroles.com |
| unset | To remove a variable. | vagrant@devopsroles:~$ unset site vagrant@devopsroles:~$ echo $site |
System Processes Management
| Commands | Description | For example |
| top | Outputs all active processes details. | |
| bg | running process to execute in the background. | |
| fg | Sends a stopped or halted process to keep executing on the foreground. | |
| ps -ef | Outputs all active or executing processes on the Linux system. | |
| ps PID | Outputs a running processes’ status in reference to its process ID. | |
| pidof | find the process ID of the running program | |
| kill PID | Kills a running process | |
| nice | lets you run a command at a priority lower than the command’s normal priority | |
| renice | alters the nice value of one or more running processes | |
| sensors | Outputs the Linux system’s CPU temperature. | |
| ps aux | To monitor processes running on your Linux system | |
| dmesg -k | Helps in troubleshooting the health status of your Linux system. | |
| program & | Executes a program in the system background. | |
| fg n | Moves a running job n to the system’s foreground. |
File Editors
| Commands | Description |
| vi | the editor is a full-screen editor and has two modes of operation |
| nano | the GNU nano editor. |
| view | an editor in view or read-only mode. |
| emacs | emacs is a screen editor |
| sed | launches stream editor |
File Utilities
| Commands | Description |
| cut | removes or deletes a file’s section. |
| diff | Command to compare files line by line. |
| head | prints the first lines (10 lines by default) of one or more files or piped data to standard output. |
| join | merges the lines of two sorted text files based on the presence of a common field. |
| more, less | to view the contents of a file, a single file page view at a time. |
| sort | to sort a file, arranging the records in a particular order. |
| split | used to split large files into smaller files. |
| tr | translating or deleting characters. |
| uniq | reports or filters out the repeated lines in a file. |
| comm | compare two sorted files line by line and write to standard output |
Performance Monitoring and Statistics
| Commands | Description |
| tcpdump -i eth1 ‘port 80’ | monitoring traffic through Port 80 |
| tcpdump -i eth1 | An interface eth1-related command for outputting captured packets. |
| watch df -h | A command to output periodic system updates. |
| lsof -u user | Outputs a list of all the files opened by a system user. |
| iostat 1 | used to get reports and statistics. |
| vmstat 1 | Outputs statistical data related to the system’s virtual memory. |
| mpstat 1 | Output processor-related statistics. |
Conclusion
Linux commands cheat sheet above. I hope will this your helpful. Thank you for reading the DevopsRoles page!
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