Show Centos Version
cat /etc/centos-release
Show computer architecture:
arch
Show kernel version
uname -r
Show system date
date
Show calendar table for 2014
cal 2014
Files and Directories
Go to '/var/www/'
cd /var/www
Go to the upper level directory
cd ..
Go to home directory
cd ~
Go to home directory of “user”
cd ~user
Show the contents of the current directory
ls
Show the contents of the current directory adding characters to the names characterizing the type
ls -F
Show detailed representation of files and directories in the current directory
ls -l
Show hidden files and directories in the current directory
ls -a
Create a directory called ‘test’
mkdir test
Create two directories simultaneously
mkdir test1 test2
Create a directory tree
mkdir -p /var/www/test/dir
Delete the file named ‘file’
rm -f file
Delete a directory named ‘dir’
rmdir dir
Delete a directory named ‘dir’ and all of its contents recursively
rm -rf dir
Rename or move a file or directory
mv dir1 new_dir
Copy file1 in file2
cp file1 file2
Create a symbolic link to a file or directory
ln -s file1 file2
Searching Files
Find files and directories named file1. Start searching from the root (/)
find / -name file1
Find files and directories owned by user1. Start searching from the root (/)
find / -user user1
Find all files and directories whose names end in ‘.log’. Start searching from ‘/var/www’
find /var/www -name "*.log"
Find all files containing '.png' in the name. it is recommended to run 'updatedb' command before this.
locate "*.png"
Find all files with '.log' extension in the current directory, including subdirectories and delete them
find . -name '*.log' -type f -delete
Disk Space
Information about partitioned sections displaying total, free and used space
df -h
Show the size used by directory ‘dir1’
du -sh dir1
Users and Groups
Create user1, assign /home/user1 as its home directory, assign /bin/bash as a shell, include it in ‘admin’ group and add a comment Nome Cognome
useradd -c "Nome Cognome" -g admin -d /home/user1 -s /bin/bash user1
Create user1
useradd user1
Delete user1 and its home directory
userdel -r user1
Create a new group named group_name
groupadd group_name
Delete group group_name
groupdel group_name
Rename group old_group_name in new_group_name
groupmod -n new_group_name old_group_name
Change password
passwd
Change password of user1 (only root)
passwd user1
Setting/Changing File Rights
Add rights 777 (Read Write Execute) to directory1 – full rights to everybody.
chmod 777 directory1
Add rights to directory1, including all files and subfolders in it, rights 777 (Read Write Execute) - full rights to everybody.
chmod –R 777 directory1
Assign user1 as the owner of file1
chown user1 file1
Recursively assign user1 as the owner of directory1
chown -R user1 directory1
Assign user 'apache' from the group 'apache' to folder 'dir', including all subfolders and files:
chown apache:apache -R /var/www/dir
Find all files in the current directory, including subfolders and assign rights 664
find . -type f -printf "\"%p\" " | xargs chmod 664
Find all folders in the current directory, including subfolders and assign rights 775
find . -type d -printf "\"%p\" " | xargs chmod 775
File Archiving and Compression
Unarchive file 'file1.bz2'
bunzip2 file1.bz2
Unarchive file 'file1.gz'
gunzip file1.gz
Archive file 'file1' to file1.gz
gzip file1
Archive file file1 to file1.bz2
bzip2 file1
Create an archive and zip it with gzip
tar -cvfz archive.tar.gz dir1
Unarchive and extract
tar -xvfz archive.tar.gz
Create zip-archive
zip file1.zip file1
Unarchive and extract zip-archive
unzip file1.zip
Upgrading Packages
Upload and install package
yum install package_name
Update all packages installed in the system
yum update
Update package
yum update package_name
Delete package
yum remove package_name
Show the list of all packages installed in the system
yum list
Find a package in the repository
yum search package_name
Clean rpm-cache, deleting uploaded packages
yum clean packages
Clean rpm-cache, deleting uploaded packages and headers
yum clean all
bunzip2 file1.bz2
Unarchive file 'file1.gz'
gunzip file1.gz
Archive file 'file1' to file1.gz
gzip file1
Archive file file1 to file1.bz2
bzip2 file1
Create an archive and zip it with gzip
tar -cvfz archive.tar.gz dir1
Unarchive and extract
tar -xvfz archive.tar.gz
Create zip-archive
zip file1.zip file1
Unarchive and extract zip-archive
unzip file1.zip
Upgrading Packages
Upload and install package
yum install package_name
Update all packages installed in the system
yum update
Update package
yum update package_name
Delete package
yum remove package_name
Show the list of all packages installed in the system
yum list
Find a package in the repository
yum search package_name
Clean rpm-cache, deleting uploaded packages
yum clean packages
Clean rpm-cache, deleting uploaded packages and headers
yum clean all
Source: https://serverdale.com/en/linux-commands