{"id":359,"date":"2022-04-24T04:57:22","date_gmt":"2022-04-24T04:57:22","guid":{"rendered":"http:\/\/www.scmgalaxy.com\/tutorials\/2014\/07\/21\/linux-commands-for-user\/"},"modified":"2024-03-27T15:32:25","modified_gmt":"2024-03-27T15:32:25","slug":"linux-commands-for-user","status":"publish","type":"post","link":"https:\/\/www.devopsschool.com\/blog\/linux-commands-for-user\/","title":{"rendered":"Linux Tutorials: Commands for Linux User"},"content":{"rendered":"\n\n\n

ls<\/code> – List directory contents.<\/h1>\n\n\n\n
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Basic Listing: Lists the visible files and directories in<\/span> the current directory.\n\n$ ls \n\nListing With Details: Displays detailed information including file permissions, number of<\/span> links, owner, group, size, and timestamp.\n\n$ ls -l\n\nListing All Files\n\nls -a: Lists all files, including hidden files (those beginning with<\/span> a dot .).\nLong Listing of<\/span> All Files\n\nls -la or ls -l -a: Combines the detailed output with<\/span> hidden files.\nListing With Human-Readable Sizes\n\nls -lh: Shows file sizes in<\/span> a human-readable format (e.g., KB, MB).\nReverse Order Listing\n\nls -r: Lists files and directories in<\/span> reverse alphabetical order.\nSorting by Modification Time\n\nls -lt: Lists files sorted by modification time, newest first.\nRecursive Listing\n\nls -R: Lists all files recursively, including the content of<\/span> subdirectories.\nListing Inodes\n\nls -i: Displays the inode number of<\/span> each file along with<\/span> the file name.\nColorized Listing\n\nls --color: Displays a colorized listing where colors signify types of<\/span> files (like directories, files, and links).<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
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cd<\/code> – Change the current directory<\/h1>\n\n\n\n
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# 1. Change to the home directory of the current user<\/span>\ncd ~\n\n# 2. Go up one level from the current directory<\/span>\ncd ..\n\n# 3. Go to the root directory<\/span>\ncd \/\n\n# 4. Change to a specific directory by path<\/span>\ncd \/usr\/local\/bin\n\n# 5. Go back to the previous directory<\/span>\ncd -\n\n# 6. Change to the user's home directory (another way)<\/span>\ncd\n\n# 7. Change to a directory with spaces in the name<\/span>\ncd \"\/path\/to\/the directory with spaces\"<\/span>\n\n# 8. Change to a directory using a relative path<\/span>\ncd .\/subfolder\n\n# 9. Change to a directory using an environment variable<\/span>\ncd $HOME\/Documents\n\n# 10. Change to a directory using a tilde expansion for another user's home directory<\/span>\ncd ~otheruser\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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pwd<\/code> – Print the name of the current working directory.<\/h1>\n\n\n\n
touch<\/code> – Create an empty file or update the access and modification times of a file.<\/h1>\n\n\n\n
mkdir<\/code> – Create a new directory.<\/h1>\n\n\n\n
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# 1. Create a single new directory<\/span>\nmkdir new_directory\n\n# 2. Create multiple directories at once<\/span>\nmkdir dir1 dir2 dir3\n\n# 3. Create a directory with intermediate directories (i.e., create parent directories as needed)<\/span>\nmkdir -p parent_directory\/sub_directory\/sub_sub_directory\n\n# 4. Create a directory with specific permissions set at the time of creation<\/span>\nmkdir -m 755<\/span> secure_directory\n\n# 5. Create directories with verbose output to show what is being done<\/span>\nmkdir -v verbose_directory\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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rm<\/code> – Remove files or directories.<\/h1>\n\n\n\n
rmdir<\/code> – Remove empty directories.<\/h1>\n\n\n\n
cp<\/code> – Copy files and directories.<\/h1>\n\n\n\n
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# 1. Copy a file to another directory<\/span>\ncp source.txt \/path\/to\/destination\/\n\n# 2. Copy multiple files to another directory<\/span>\ncp source1.txt source2.txt \/path\/to\/destination\/\n\n# 3. Copy a file and rename it in the destination<\/span>\ncp source.txt \/path\/to\/destination\/renamed.txt\n\n# 4. Copy a directory recursively to another location<\/span>\ncp -r \/path\/to\/sourceDir \/path\/to\/destinationDir\n\n# 5. Copy files with verbose output (shows files as they are copied)<\/span>\ncp -v source.txt \/path\/to\/destination\/\n\n# 6. Copy all files with a specific extension<\/span>\ncp *.txt \/path\/to\/destination\/\n\n# 7. Copy all files and directories within a directory to another location<\/span>\ncp -R \/path\/to\/sourceDir\/* \/path\/to\/destinationDir\/\n\n# 8. Preserve the mode, ownership, and timestamps\ncp -p source.txt \/path\/to\/destination\/\n\n# 9. Copy a directory to another location, overwriting files in the destination\ncp -rT \/path\/to\/sourceDir \/path\/to\/destinationDir\n\n# 10. Copy a file interactively, prompting before overwrite\ncp -i source.txt \/path\/to\/destination\/\n<\/span><\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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mv<\/code> – Move or rename files and directories.<\/h1>\n\n\n\n
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# 1. Rename a file<\/span>\nmv oldname.txt newname.txt\n\n# 2. Move a file to another directory<\/span>\nmv filename.txt \/path\/to\/destination\/\n\n# 3. Move multiple files to another directory<\/span>\nmv file1.txt file2.txt \/path\/to\/destination\/\n\n# 4. Move and rename a file in one operation<\/span>\nmv oldfile.txt \/path\/to\/destination\/newfile.txt\n\n# 5. Rename a directory<\/span>\nmv oldDirName newDirName\n\n# 6. Move a directory to another location<\/span>\nmv \/path\/to\/sourceDir \/path\/to\/destinationDir\n\n# 7. Move multiple directories to another directory<\/span>\nmv dir1 dir2 \/path\/to\/destination\/\n\n# 8. Use wildcard to move multiple files of a specific type<\/span>\nmv *.txt \/path\/to\/destination\/\n\n# 9. Move files interactively, prompting before overwrite<\/span>\nmv -i source.txt \/path\/to\/destination\/\n\n# 10. Verbosely move files, showing files as they are moved<\/span>\nmv -v file1.txt \/path\/to\/destination\/\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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echo<\/code> – Display a line of text\/string to the terminal.<\/h1>\n\n\n\n
cat<\/code> – Concatenate and display the content of files.<\/h1>\n\n\n\n
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# 1. Display the content of a single file<\/span>\ncat file1.txt\n\n# 2. Concatenate multiple files and display the content<\/span>\ncat file1.txt file2.txt\n\n# 3. Concatenate files and redirect the output to a new file<\/span>\ncat file1.txt file2.txt > combined.txt\n\n# 4. Append content of one file to another<\/span>\ncat file1.txt >> file2.txt\n\n# 5. Display line numbers while viewing the content of a file<\/span>\ncat -n file1.txt\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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more<\/code> – View file content page by page.<\/h1>\n\n\n\n
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# 1. View the contents of a file page by page<\/span>\nmore filename.txt\n\n# 2. View multiple files sequentially<\/span>\nmore file1.txt file2.txt\n\n# 3. Display a specific number of lines at a time<\/span>\nmore -num 20<\/span> filename.txt\n\n# 4. Start viewing from a specific line<\/span>\nmore +100<\/span> filename.txt\n\n# 5. View the contents of a file with line numbers<\/span>\nmore -n filename.txt\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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less<\/code> – View file content with backward navigation support.<\/h1>\n\n\n\n
grep<\/code> – Search for patterns within files.<\/h1>\n\n\n\n
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# 1. Search for a specific string in a file<\/span>\ngrep \"pattern\"<\/span> filename.txt\n\n# 2. Search for a pattern in multiple files<\/span>\ngrep \"pattern\"<\/span> file1.txt file2.txt\n\n# 3. Count the number of lines that match the pattern<\/span>\ngrep -c \"pattern\"<\/span> filename.txt\n\n# 4. Display line numbers with the lines that match the pattern<\/span>\ngrep -n \"pattern\"<\/span> filename.txt\n\n# 5. Search for a pattern in all files in a directory<\/span>\ngrep \"pattern\"<\/span> \/path\/to\/directory\/*\n\n# 6. Ignore case while searching\ngrep -i \"pattern\" filename.txt\n\n# 7. Search for a pattern recursively in all files in a directory and subdirectories\ngrep -r \"pattern\" \/path\/to\/directory\n\n# 8. Invert match to display lines that do not contain the pattern\ngrep -v \"pattern\" filename.txt\n\n# 9. Search for lines that match one of multiple patterns\ngrep -e \"pattern1\" -e \"pattern2\" filename.txt\n\n# 10. Display only the names of files with lines matching the pattern\ngrep -l \"pattern\" \/path\/to\/directory\/*\n<\/span><\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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find<\/code> – Search for files in a directory hierarchy.<\/h1>\n\n\n\n
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# 1. Find all files in the current directory and its subdirectories<\/span>\nfind .\n\n# 2. Find all files with a specific name<\/span>\nfind \/path\/to\/search -name filename.txt\n\n# 3. Find all files with a specific extension in a directory<\/span>\nfind \/path\/to\/search -type f -name \"*.txt\"<\/span>\n\n# 4. Find and delete all files with a specific extension<\/span>\nfind \/path\/to\/search -type f -name \"*.tmp\"<\/span> -delete\n\n# 5. Find directories with a specific name<\/span>\nfind \/path\/to\/search -type d -name \"dirName\"<\/span>\n\n# 6. Find files larger than a certain size<\/span>\nfind \/path\/to\/search -type f -size +100<\/span>M\n\n# 7. Find files modified in the last 7 days<\/span>\nfind \/path\/to\/search -type f -mtime -7<\/span>\n\n# 8. Find files accessed in the last 24 hours<\/span>\nfind \/path\/to\/search -type f -atime -1<\/span>\n\n# 9. Find files with specific permissions<\/span>\nfind \/path\/to\/search -type f -perm 0644<\/span>\n\n# 10. Execute a command on all found files<\/span>\nfind \/path\/to\/search -type f -name \"*.txt\"<\/span> -exec cat {} \\;\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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chmod<\/code> – Change file access permissions.<\/h1>\n\n\n\n
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# 1. Give the owner (user) execute permission on a file<\/span>\r\nchmod u+x filename\r\n\r\n# 2. Remove write permission from the group and others for a file<\/span>\r\nchmod go-w filename\r\n\r\n# 3. Set read and write permissions for the owner, and read permission for the group, no permissions for others<\/span>\r\nchmod 640<\/span> filename\r\n\r\n# 4. Set read, write, and execute permissions for the owner, and read and execute permissions for the group and others<\/span>\r\nchmod 755<\/span> filename\r\n\r\n# 5. Add execute permission for all (user, group, and others) on a file<\/span>\r\nchmod a+x filename\r\n\r\n# 6. Remove all permissions for the group and others<\/span>\r\nchmod go= filename\r\n\r\n# 7. Set the exact permissions for a file (read and write for owner, read for group, none for others)<\/span>\r\nchmod 640<\/span> filename\r\n\r\n# 8. Recursively give the owner and group read and write permissions on a directory and its contents, while removing all permissions for others<\/span>\r\nchmod -R 660<\/span> directoryname\r\n\r\n# 9. Ensure a file is executable by everyone<\/span>\r\nchmod a+x filename\r\n\r\n# 10. Set sticky bit on a directory to prevent deletion of files by non-owners<\/span>\r\nchmod +t directoryname\r\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
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chown<\/code> – Change file owner and group.<\/h1>\n\n\n\n
head<\/code> – Output the first part of files.<\/h1>\n\n\n\n
tail<\/code> – Output the last part of files.<\/h1>\n\n\n\n
diff<\/code> – Compare files line by line.<\/h1>\n\n\n\n
tar<\/code> – Archive files.<\/h1>\n\n\n\n
wget<\/code> – Non-interactive network downloader.<\/h1>\n\n\n\n
curl<\/code> – Transfer data from or to a server.<\/h1>\n\n\n\n
ssh<\/code> – Secure Shell, a protocol to securely access remote machines.<\/h1>\n\n\n\n
scp<\/code> – Secure copy (remote file copy program).<\/h1>\n\n\n\n
ps<\/code> – Report a snapshot of current processes.<\/h1>\n\n\n\n
top<\/code> – Display Linux processes.<\/h1>\n\n\n\n
kill<\/code> – Send a signal to a process.<\/h1>\n\n\n\n
nano<\/code> – Command-line text editor.<\/h1>\n\n\n\n
vi<\/code> – Visual text editor.<\/h1>\n\n\n\n
sudo<\/code> – Execute a command as another user, typically the superuser.<\/h1>\n\n\n\n
df<\/code> – Report file system disk space usage.<\/h1>\n\n\n\n
du<\/code> – Estimate file space usage.<\/h1>\n\n\n\n
man<\/code> – An interface to the system reference manuals.<\/h1>\n\n\n\n
whatis<\/code> – Display one-line manual page descriptions.<\/h1>\n\n\n\n
alias<\/code> – Create an alias for a command.<\/h1>\n\n\n\n
unalias<\/code> – Remove an alias.<\/h1>\n\n\n\n
apt-get<\/code> – Command-line tool for handling packages (Debian-based systems).<\/h1>\n\n\n\n
yum<\/code> – Command-line package-management utility (Red Hat-based systems).<\/h1>\n\n\n\n
dnf<\/code> – Fedora package manager.<\/h1>\n\n\n\n
mount<\/code> – Mount a filesystem.<\/h1>\n\n\n\n
umount<\/code> – Unmount a filesystem.<\/h1>\n\n\n\n
systemctl<\/code> – Control the systemd system and service manager.<\/h1>\n\n\n\n
journalctl<\/code> – Query and display messages from the journal.<\/h1>\n\n\n\n
netstat<\/code> – Network statistics.<\/h1>\n\n\n\n
ping<\/code> – Send ICMP ECHO_REQUEST to network hosts.<\/h1>\n\n\n\n
ifconfig<\/code> – Configure a network interface.<\/h1>\n\n\n\n
traceroute<\/code> – Trace the route taken by packets over an IPv4\/IPv6 network.<\/h1>\n\n\n\n
ip<\/code> – Show \/ manipulate routing, network devices, interfaces, and tunnels.<\/h1>\n\n\n\n
crontab<\/code> – Schedule commands to run at a set time.<\/h1>\n\n\n\n
useradd<\/code> – Create a new user or update default new user information.<\/h1>\n\n\n\n
passwd<\/code> – Update a user’s authentication token(s).<\/h1>\n\n\n\n
File Commands<\/h3>\n\n\n\n
List files in the directory:<\/strong><\/p>\n\n\n
ls<\/code><\/span><\/pre>\n\n\n
List all files<\/strong>:<\/p>\n\n\n
ls -a<\/code><\/span><\/pre>\n\n\n
Show directory you are currently working in:<\/strong><\/p>\n\n\n
pwd<\/code><\/span><\/pre>\n\n\n
Create a new directory:<\/strong><\/p>\n\n\n
mkdir<\/span> [directory]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Remove a file:<\/strong><\/p>\n\n\n
rm<\/span> [file_name]<\/span> <\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Remove a directory recursively:<\/strong><\/p>\n\n\n
rm<\/span> -r<\/span> [directory_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Recursively remove a directory without requiring confirmation:<\/strong><\/p>\n\n\n
rm<\/span> -rf<\/span> [directory_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Copy the contents of one file to another file:<\/strong><\/p>\n\n\n
cp<\/span> [file_name1]<\/span> [file_name2]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Recursively copy the contents of one file to a second file:<\/strong><\/p>\n\n\n
cp<\/span> -r<\/span> [directory_name1]<\/span> [directory_name2]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Rename [file_name1]<\/code> to [file_name2]<\/code> with the command:<\/strong><\/p>\n\n\n
mv<\/span> [file_name1]<\/span> [file_name2]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Create a symbolic link to a file:<\/strong><\/p>\n\n\n
ln -s \/path\/to\/[file_name] [link_name]<\/code><\/span><\/pre>\n\n\n
Create a new file using touch:<\/strong><\/p>\n\n\n
touch<\/span> [file_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Show the contents of a file:<\/strong><\/p>\n\n\n
more<\/span> [file_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
or use the cat<\/code> command:<\/strong><\/p>\n\n\n
cat<\/span> [file_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Append file contents to another file:<\/strong><\/p>\n\n\n
cat<\/span> [file_name1]<\/span> >> [file_name2]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Display the first 10 lines of a file with head command:<\/strong><\/p>\n\n\n
head<\/span> [file_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Show the last 10 lines of a file:<\/strong><\/p>\n\n\n
tail<\/span> [file_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Encrypt a file:<\/strong><\/p>\n\n\n
gpg<\/span> -c<\/span> [file_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Decrypt a file:<\/strong><\/p>\n\n\n
gpg<\/span> [file_name.gpg]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Show the number of words, lines, and bytes in a file using wc:<\/strong><\/p>\n\n\n
wc<\/code><\/span><\/pre>\n\n\n
List number of lines\/words\/characters in each file in a directory with the xargs command:<\/strong><\/p>\n\n\n
ls | xargs wc<\/code><\/span><\/pre>\n\n\n
Cut a section of a file and print the result to standard output:<\/strong><\/p>\n\n\n
cut<\/span> -d<\/span>[delimiter]<\/span> [filename]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Cut a section of piped data and print the result to standard output:<\/strong><\/p>\n\n\n
[data] | cut -d[delimiter]<\/code><\/span><\/pre>\n\n\n
Print all lines matching a pattern in a file:<\/strong><\/p>\n\n\n
awk '[pattern] {print $0}'<\/span> [filename]<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Overwrite a file to prevent its recovery, then delete it:<\/strong><\/p>\n\n\n
shred<\/span> -u<\/span> [filename]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Compare two files and display differences:<\/strong><\/p>\n\n\n
diff<\/span> [file1]<\/span> [file2]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Read and execute the file content in the current shell:<\/strong><\/p>\n\n\n
source<\/span> [filename]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Sort file contents and print the result in standard output:<\/strong><\/p>\n\n\n
sort<\/span> [options]<\/span> filename<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Store the command output in a file and skip the terminal output:<\/strong><\/p>\n\n\n\n
Directory Navigation<\/h3>\n\n\n\n
Move up one level in the directory tree structure:<\/strong><\/p>\n\n\n
cd ..<\/code><\/span><\/pre>\n\n\n
Change directory to $HOME<\/code>:<\/strong><\/p>\n\n\n
cd<\/code><\/span><\/pre>\n\n\n
Change location to a specified directory:<\/strong><\/p>\n\n\n
cd \/chosen\/directory<\/code><\/span><\/pre>\n\n\n
File Compression<\/h3>\n\n\n\n
Archive an existing file:<\/strong><\/p>\n\n\n
tar<\/span> cf<\/span> [compressed_file.tar]<\/span> [file_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Extract an archived file:<\/strong><\/p>\n\n\n
tar<\/span> xf<\/span> [compressed_file.tar]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Create a gzip compressed tar file by running:<\/strong><\/p>\n\n\n
tar<\/span> czf<\/span> [compressed_file.tar.gz]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Compress a file with the .gz<\/code> extension:<\/strong><\/p>\n\n\n\n
File Transfer<\/h3>\n\n\n\n
Copy a file to a server directory securely using the Linux scp command:<\/strong><\/p>\n\n\n
scp<\/span> [file_name.txt]<\/span> [server\/tmp]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Synchronize the contents of a directory with a backup directory using the rsync command:<\/strong><\/p>\n\n\n
rsync -a [\/your\/<\/span>directory] [\/backup\/<\/span>] <\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Users and Groups<\/h3>\n\n\n\n
See details about the active users:<\/strong><\/p>\n\n\n
id<\/code><\/span><\/pre>\n\n\n
Show last system logins:<\/strong><\/p>\n\n\n
last<\/code><\/span><\/pre>\n\n\n
Display who is currently logged into the system with the who command:<\/strong><\/p>\n\n\n
who<\/code><\/span><\/pre>\n\n\n
Show which users are logged in and their activity:<\/strong><\/p>\n\n\n
w<\/code><\/span><\/pre>\n\n\n
Add a new group by typing:<\/strong><\/p>\n\n\n
groupadd<\/span> [group_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Add a new user:<\/strong><\/p>\n\n\n
adduser<\/span> [user_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Add a user to a group:<\/strong><\/p>\n\n\n
usermod<\/span> -aG<\/span> [group_name]<\/span> [user_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Temporarily elevate user privileges to superuser or root using the sudo command:<\/strong><\/p>\n\n\n
sudo<\/span> [command_to_be_executed_as_superuser]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Delete a user:<\/strong><\/p>\n\n\n
userdel<\/span> [user_name]<\/span> <\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Modify user information with:<\/strong><\/p>\n\n\n
usermod<\/code><\/span><\/pre>\n\n\n
Change directory group:<\/strong><\/p>\n\n\n
chgrp<\/span> [group-name]<\/span> [directory-name]<\/span>\n<\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Package Installation<\/h3>\n\n\n\n
List all installed packages with yum<\/code>:<\/strong><\/p>\n\n\n
yum list<\/span> installed<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Find a package by a related keyword:<\/strong><\/p>\n\n\n
yum<\/span> search<\/span> [keyword]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Show package information and summary:<\/strong><\/p>\n\n\n
yum<\/span> info<\/span> [package_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Install a package using the YUM package manager:<\/strong><\/p>\n\n\n
yum<\/span> install<\/span> [package_name.rpm]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Install a package using the DNF package manager:<\/strong><\/p>\n\n\n
dnf<\/span> install<\/span> [package_name.rpm]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Install a package using the APT package manager:<\/strong><\/p>\n\n\n
apt<\/span> install<\/span> [package_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Install an .rpm<\/code> package from a local file:<\/strong><\/p>\n\n\n
rpm<\/span> -i<\/span>  [package_name.rpm]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Remove an .rpm<\/code> package:<\/strong><\/p>\n\n\n
rpm<\/span> -e<\/span> [package_name.rpm]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Install software from source code:<\/strong><\/p>\n\n\n
tar zxvf [source_code.tar.gz]\ncd [source_code]\n.\/configure\nmake\nmake install<\/code><\/span><\/pre>\n\n\n
Process Related<\/h3>\n\n\n\n
See a snapshot of active processes:<\/strong><\/p>\n\n\n
ps<\/code><\/span><\/pre>\n\n\n
Show processes in a tree-like diagram:<\/strong><\/p>\n\n\n
pstree<\/code><\/span><\/pre>\n\n\n
Display a memory usage map of processes:<\/strong><\/p>\n\n\n
pmap<\/code><\/span><\/pre>\n\n\n
See all running processes:<\/strong><\/p>\n\n\n
top<\/code><\/span><\/pre>\n\n\n
Terminate a Linux process under a given ID:<\/strong><\/p>\n\n\n
kill<\/span> [process_id]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Terminate a process under a specific name:<\/strong><\/p>\n\n\n
pkill<\/span> [proc_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Terminate all processes labelled \u201cproc\u201d:<\/strong><\/p>\n\n\n
killall<\/span> [proc_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
List and resume stopped jobs in the background:<\/strong><\/p>\n\n\n
bg<\/code><\/span><\/pre>\n\n\n
Bring the most recently suspended job to the foreground:<\/strong><\/p>\n\n\n
fg<\/code><\/span><\/pre>\n\n\n
Bring a particular job to the foreground:<\/strong><\/p>\n\n\n
fg<\/span> [job]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
List files opened by running processes:<\/strong><\/p>\n\n\n
lsof<\/code><\/span><\/pre>\n\n\n
Catch a system error signal in a shell script:<\/strong><\/p>\n\n\n
trap<\/span> \"[commands-to-execute-on-trapping]<\/span>\" [signal]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Pause terminal or a Bash script until a running process is completed:<\/strong><\/p>\n\n\n
wait<\/code><\/span><\/pre>\n\n\n
Run a Linux process in the background:<\/strong><\/p>\n\n\n
nohup<\/span> [command]<\/span> &\n\n<\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
System Management and Information<\/h3>\n\n\n\n
Show system information<\/strong>:<\/p>\n\n\n
uname -r <\/code><\/span><\/pre>\n\n\n
See kernel release information:<\/strong><\/p>\n\n\n
uname -a  <\/code><\/span><\/pre>\n\n\n
Display how long the system has been running, including load average:<\/strong><\/p>\n\n\n
uptime <\/code><\/span><\/pre>\n\n\n
See system hostname:<\/strong><\/p>\n\n\n
hostname<\/code><\/span><\/pre>\n\n\n
Show the IP address of the system:<\/strong><\/p>\n\n\n
hostname -i <\/code><\/span><\/pre>\n\n\n
List system reboot history:<\/strong><\/p>\n\n\n
last reboot <\/code><\/span><\/pre>\n\n\n
See current time and date:<\/strong><\/p>\n\n\n
date<\/code><\/span><\/pre>\n\n\n
Query and change the system clock with:<\/strong><\/p>\n\n\n
timedatectl <\/code><\/span><\/pre>\n\n\n
Show current calendar (month and day):<\/strong><\/p>\n\n\n
cal<\/code><\/span><\/pre>\n\n\n
List logged in users:<\/strong><\/p>\n\n\n
w<\/code><\/span><\/pre>\n\n\n
See which user you are using:<\/strong><\/p>\n\n\n
whoami<\/code><\/span><\/pre>\n\n\n
Show information about a particular user:<\/strong><\/p>\n\n\n
finger<\/span> [username]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
View or limit system resource amounts:<\/strong><\/p>\n\n\n
ulimit<\/span> [flags]<\/span> [limit]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Schedule a system shutdown:<\/strong><\/p>\n\n\n
shutdown<\/span> [hh:mm]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Shut Down the system immediately:<\/strong><\/p>\n\n\n
shutdown now<\/code><\/span><\/pre>\n\n\n
Add a new kernel module:<\/strong><\/p>\n\n\n
modprobe [module<\/span>-name]<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Disk Usage<\/h3>\n\n\n\n
You can use the df and du commands to check disk space in Linux.<\/p>\n\n\n\n
See free and used space on mounted systems:<\/strong><\/p>\n\n\n
df -h<\/code><\/span><\/pre>\n\n\n
Show free inodes on mounted filesystems:<\/strong><\/p>\n\n\n
df -i<\/code><\/span><\/pre>\n\n\n
Display disk partitions, sizes, and types with the command:<\/strong><\/p>\n\n\n
fdisk -l<\/code><\/span><\/pre>\n\n\n
See disk usage for all files and directory:<\/strong><\/p>\n\n\n
du -ah<\/code><\/span><\/pre>\n\n\n
Show disk usage of the directory you are currently in:<\/strong><\/p>\n\n\n
du -sh<\/code><\/span><\/pre>\n\n\n
Display target mount point for all filesystem:<\/strong><\/p>\n\n\n
findmnt<\/code><\/span><\/pre>\n\n\n
Mount a device<\/strong>:<\/p>\n\n\n
mount<\/span> [device_path]<\/span> [mount_point]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
SSH Login<\/h3>\n\n\n\n
Connect to host as user:<\/strong><\/p>\n\n\n
ssh<\/span> user<\/span>@host<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Securely connect to host via SSH default port 22:<\/strong><\/p>\n\n\n
ssh host<\/code><\/span><\/pre>\n\n\n
Connect to host using a particular port:<\/strong><\/p>\n\n\n
ssh<\/span> -p<\/span> [port]<\/span> user<\/span>@host<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Connect to host via telnet default port 23:<\/strong><\/p>\n\n\n
telnet host<\/code><\/span><\/pre>\n\n\n
File Permission<\/h3>\n\n\n\n
Chown command in Linux changes file and directory ownership.<\/p>\n\n\n\n
Assign read, write, and execute permission to everyone:<\/strong><\/p>\n\n\n
chmod<\/span> 777 [file_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Give read, write, and execute permission to owner, and read and execute permission to group and others:<\/strong><\/p>\n\n\n
chmod<\/span> 755 [file_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Assign full permission to owner, and read and write permission to group and others:<\/strong><\/p>\n\n\n
chmod<\/span> 766 [file_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Change the ownership of a file:<\/strong><\/p>\n\n\n
chown<\/span> [user]<\/span> [file_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Change the owner and group ownership of a file:<\/strong><\/p>\n\n\n
chown<\/span> [user]<\/span>:[group]<\/span> [file_name]<\/span>\n\n<\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Network<\/h3>\n\n\n\n
List IP addresses and network interfaces:<\/strong><\/p>\n\n\n
ip addr show<\/code><\/span><\/pre>\n\n\n
Assign an IP address to interface eth0:<\/strong><\/p>\n\n\n
ip<\/span> address<\/span> add<\/span> [IP_address]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Display IP addresses of all network interfaces with:<\/strong><\/p>\n\n\n
ifconfig<\/code><\/span><\/pre>\n\n\n
See active (listening) ports with the netstat command:<\/strong><\/p>\n\n\n
netstat -pnltu<\/code><\/span><\/pre>\n\n\n
Show tcp and udp ports and their programs:<\/strong><\/p>\n\n\n
netstat -nutlp<\/code><\/span><\/pre>\n\n\n
Display more information about a domain:<\/strong><\/p>\n\n\n
whois<\/span> [domain]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Show DNS information about a domain using the dig command:<\/strong><\/p>\n\n\n
dig<\/span> [domain]<\/span> <\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Do a reverse lookup on domain:<\/strong><\/p>\n\n\n
dig -x host<\/code><\/span><\/pre>\n\n\n
Do reverse lookup of an IP address:<\/strong><\/p>\n\n\n
dig<\/span> -x<\/span> [ip_address]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Perform an IP lookup for a domain:<\/strong><\/p>\n\n\n
host<\/span> [domain]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Show the local IP address:<\/strong><\/p>\n\n\n
hostname -I<\/code><\/span><\/pre>\n\n\n
Download a file from a domain using the wget<\/code> command:<\/strong><\/p>\n\n\n
wget<\/span> [file_name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Receive information about an internet domain:<\/strong><\/p>\n\n\n
nslookup<\/span> [domain-name]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Save a remote file to your system using the filename that corresponds to the filename on the server:<\/strong><\/p>\n\n\n
curl<\/span> -O<\/span> [file-url]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Variables<\/h3>\n\n\n\n
Assign an integer value to a variable:<\/strong><\/p>\n\n\n
let<\/span> \"[variable]=[value]\"<\/span><\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Export a Bash variable:<\/strong><\/p>\n\n\n
export<\/span> [variable-name]<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Declare a Bash variable:<\/strong><\/p>\n\n\n
declare<\/span> [variable-name]= \"[value]\"<\/span><\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
List the names of all the shell variables and functions:<\/strong><\/p>\n\n\n
set<\/span><\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Display the value of a variable:<\/strong><\/p>\n\n\n
echo<\/span> $[variable-name]<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
Shell Command Management<\/h3>\n\n\n\n
Create an alias for a command:<\/strong><\/p>\n\n\n
alias [alias-name]='[command]'<\/span><\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Set a custom interval to run a user-defined command:<\/strong><\/p>\n\n\n
watch<\/span> -n<\/span> [interval-in-seconds]<\/span> [command]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Postpone the execution of a command:<\/strong><\/p>\n\n\n
sleep<\/span> [time-interval]<\/span> && [command]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Create a job to be executed at a certain time (Ctrl+D to exit prompt after you type in the command):<\/strong><\/p>\n\n\n
at<\/span> [hh:mm]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Display a built-in manual for a command:<\/strong><\/p>\n\n\n
man<\/span> [command]<\/span><\/code><\/span>Code language:<\/span> CSS<\/span> (<\/span>css<\/span>)<\/span><\/small><\/pre>\n\n\n
Print the history of the commands you used in the terminal:<\/strong><\/p>\n\n\n
history<\/code><\/span><\/pre>\n\n\n
Linux Keyboard Shortcuts<\/h3>\n\n\n\n
Kill process running in the terminal:<\/strong><\/p>\n\n\n
Ctrl + C<\/code><\/span><\/pre>\n\n\n
Stop current process:<\/strong><\/p>\n\n\n
Ctrl + Z<\/code><\/span><\/pre>\n\n\n
The process can be resumed in the foreground with fg<\/code> or in the background with bg<\/code>.<\/strong><\/p>\n\n\n\n
Cut one word before the cursor and add it to clipboard:<\/strong><\/p>\n\n\n
Ctrl + W<\/code><\/span><\/pre>\n\n\n
Cut part of the line before the cursor and add it to clipboard:<\/strong><\/p>\n\n\n
Ctrl + U<\/code><\/span><\/pre>\n\n\n
Cut part of the line after the cursor and add it to clipboard:<\/strong><\/p>\n\n\n
Ctrl + K<\/code><\/span><\/pre>\n\n\n
Paste from clipboard:<\/strong><\/p>\n\n\n
Ctrl + Y<\/code><\/span><\/pre>\n\n\n
Recall last command that matches the provided characters:<\/strong><\/p>\n\n\n
Ctrl + R<\/code><\/span><\/pre>\n\n\n
Run the previously recalled command:<\/strong><\/p>\n\n\n
Ctrl + O<\/code><\/span><\/pre>\n\n\n
Exit command history without running a command:<\/strong><\/p>\n\n\n
Ctrl + G<\/code><\/span><\/pre>\n\n\n
Run the last command again:<\/strong><\/p>\n\n\n
!!<\/code><\/span><\/pre>\n\n\n
Log out of current session:<\/strong><\/p>\n\n\n
exit<\/span>\n<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
file<\/h2>\n\n\n\n
file command is used to determine the type of a file. .file type may be of human-readable(e.g. ‘ASCII text’) or MIME type(e.g. ‘text\/plain; charset=us-ascii’). This command tests each argument in an attempt to categorize it.<\/p>\n\n\n\n
It has three sets of tests as follows:<\/p>\n\n\n\n
    \n
  • filesystem test: This test is based on the result which returns from a stat system call. The program verifies that if the file is empty, or if it\u2019s some sort of special file. This test causes the file type to be printed.<\/li>\n\n\n\n
  • magic test: These tests are used to check for files with data in particular fixed formats.<\/li>\n\n\n\n
  • language test: This test search for particular strings which can appear anywhere in the first few blocks of a file.<\/li>\n<\/ul>\n\n\n
    $ file email.py\n$ file name.jpeg\n$ file Invoice.pdf\n$ file exam.ods\n$ file videosong.mp4\n$ man file<\/code><\/span><\/pre>\n\n\n
    \"\"<\/figure>\n\n\n\n
    \"\"<\/figure>\n\n\n\n
    ‘cmp’ command in Linux with examples<\/h2>\n\n\n\n
    cmp command in Linux\/UNIX is used to compare the two files byte by byte and helps you to find out whether the two files are identical or not.<\/p>\n\n\n\n
      \n
    • When cmp is used for comparison between two files, it reports the location of the first mismatch to the screen if difference is found and if no difference is found i.e the files compared are identical.<\/li>\n\n\n\n
    • cmp displays no message and simply returns the prompt if the the files compared are identical.<\/li>\n<\/ul>\n\n\n\n
      \"\"<\/figure>\n\n\n
      $ cat sample.txt\nThis is a sample text file\n\n$ cat sample1.txt\nThis is another sample file\n\n$ cmp sample.txt sample1.txt\nsample.txt sample1.txt differ: byte 10<\/span>, line 1<\/span>\n\n# How to compare two files using cmp<\/span>\n$ cmp file1.txt file2.txt\n\n# How to make cmp print differing bytes<\/span>\n$ cmp -b file1.txt  file2.txt\n\n# How to make cmp skip some initial bytes from both files<\/span>\n$ cmp -i 10<\/span> file1.txt  file2.txt\n\n# How to make cmp display byte position (and value) for all differing bytes<\/span>\n$ cmp -l file1.txt  file2.txt\n\n# How to limit number of bytes to be compared<\/span>\n$ cmp -n 25<\/span>  file1.txt  file2.txt\n\n# How to display progress meter while using cmp command<\/span>\n$ pv file1.txt | cmp -l file3.txt > output.txt\n\n# How to make 'cmp' suppress output<\/span>\n$ cmp -s file1.txt file2.txt<\/code><\/span>Code language:<\/span> PHP<\/span> (<\/span>php<\/span>)<\/span><\/small><\/pre>\n\n\n
      ‘comm’ command in Linux with examples<\/h2>\n\n\n\n
      comm compare two sorted files line by line and write to standard output; the lines that are common and the lines that are unique.<\/p>\n\n\n\n
      \"\"<\/figure>\n\n\n\n
      \"\"<\/figure>\n\n\n\n
      \"\"<\/figure>\n\n\n\n
      \n