Shell commands table

Category	Command	Sub-command	Description
File Operations and Text Processing	cat	cat filename	Displays the contents of filename.
		cat file1 file2 > combined_file	Concatenates file1 and file2 into combined_file.
	grep	grep "pattern" file	Searches for "pattern" in file.
		grep -r "pattern" directory/	Recursively searches for "pattern" in directory and its subdirectories.
		grep -i "pattern" file	Searches for "pattern" in file case-insensitively.
	sed	sed 's/old/new/g' file	Replaces all occurrences of "old" with "new" in file.
		sed -i '1d' file	Deletes the first line of file in place.
	awk	awk -F"\\t" '{print $8}' file	Prints the 8th column of a tab-separated file.
		awk '{sum += $1} END {print sum}' file	Sums the first column of file and prints the total.
	sort	sort file	Sorts the lines in file alphabetically.
		sort -t $'\\t' -k 2 file	Sorts file based on the second tab-separated column.
		sort -t $'\\t' -rk 2 file	Sorts file in reverse order based on the second tab-separated column.
	uniq	uniq file	Removes duplicate lines from file.
		uniq -c file	Counts the number of occurrences of each line in file.
	split	split -l 10000 file.txt	Splits file.txt into smaller files with 10,000 lines each.
	wc	wc -l file	Counts the number of lines in file.
		wc -w file	Counts the number of words in file.
	join	join file1 file2	Joins lines of file1 and file2 on a common field.
	head	head -n 100 filename	Displays the first 100 lines of filename.
	tail	tail -n +1000 filename	Displays lines starting from line 1000 of filename.
Data Statistics and Analysis	xargs	ls | xargs grep "pattern"
	tee	command | tee file
		command | tee -a file
Compression and Archiving	gzip	gzip filename	Compresses filename using the gzip algorithm.
		gzip -d filename.gz	Decompresses filename.gz.
	tar	tar -cvf archive.tar /path/to/directory	Creates a tar archive without compression.
		tar -zcvf archive.tar.gz /path/to/directory	Creates a tar archive with gzip compression.
		tar -xf archive.tar -C /destination	Extracts a tar archive to the specified destination.
		tar -xzf archive.tar.gz -C /destination	Extracts a gzip-compressed tar archive to the specified destination.
		tar -cvf archive.tar /path --exclude=*log* --exclude=*data*	Creates a tar archive while excluding files matching patterns.
	zip	zip archive.zip file1 file2	Compresses file1 and file2 into archive.zip.
		zip -r archive.zip directory/	Recursively compresses directory into archive.zip.
Data Flow and Process Management	ps	ps aux --sort=-%mem	Lists processes sorted by memory usage.
		ps -ef	Displays all running processes.
		ps -eaf	Another variant to display all processes.
	top	top	Displays real-time system processes and resource usage.
	kill	kill -9 $pid	Forcefully terminates a process with the specified PID.
	pgrep	pgrep process_name	Searches for processes by name and returns their PIDs.
	bg	bg %job	Resumes a suspended job in the background.
	jobs	jobs	Lists active jobs in the current shell.
	nohup	nohup command > output.log 2>&1 &	Runs command immune to hangups, redirecting output to output.log and running it in the background.
Network and File Transfer	wget	wget <http://example.com/file.zip>	Retrieves file.zip from the specified URL.
		wget -O output.txt <http://example.com/data>	Downloads data from the specified URL and saves it as output.txt.
	scp	scp file.txt user@remote:/path/	Securely copies file.txt to a remote host.
		scp -r /local/dir user@remote:/path/	Securely copies a directory recursively to a remote host.
	netstat	netstat -tunpl \| grep [port]	Lists listening ports and associated processes.
		netstat -nap \| grep [pid]	Shows network connections for a specific PID.
	nc (netcat)	nc -zv host port	Scans host on port to check if it's open.
		nc host port	Connects to host on port for data transfer or communication.
System Information and Monitoring	df	df -h	Reports file system disk space usage in a human-readable format.
		df -T	Shows the type of file system.
	du	du -h --max-depth=1	Displays disk usage in a human-readable format, limited to one directory level.
		du -sh test_dir	Shows the total disk usage of test_dir.
	iostat	iostat	Reports CPU and I/O statistics for devices and partitions.
File Search	find	find . -name "*.log"	Searches for all .log files in the current directory and subdirectories.
		find /path -type f -size +100M	Finds files larger than 100MB in /path.
	which	which gcc	Locates the executable path for gcc.
Permission Management	chmod	chmod u+r file	Adds read permission for the user on file.
		chmod o-r file	Removes read permission for others on file.
		chmod 755 script.sh	Sets permissions to rwxr-xr-x for script.sh.
	chown	chown user:group file	Changes ownership of file to user and group.
		chown -R user:group directory/	Recursively changes ownership of directory and its contents to user and group.
	ls -l	ls -l	Lists directory contents in long format, showing permissions and ownership.
Other Tools	env	env	Displays the current environment variables.
		env VAR=value command	Sets an environment variable VAR to value for the duration of command.
	date	date	Displays the current date and time.
		date +"%Y-%m-%d"	Outputs the date in YYYY-MM-DD format.
	watch	watch -n 1 ls	Executes ls every second, updating the display.
	alias	alias ll='ls -al'	Creates an alias ll for ls -al.
		alias gs='git status'	Creates an alias gs for git status.
Advanced Tools	jq	jq '.' file.json	Parses and formats JSON data from file.json.
		jq '.key' file.json	Extracts the value of key from file.json.
Network Configuration and Management	netplan	netplan apply	Applies the network configuration defined in Netplan YAML files.
	ip	ip addr add 10.240.224.117/24 dev ens9f0	Adds an IP address to the network interface ens9f0.
		ip route add default via 10.240.224.1	Adds a default gateway route via 10.240.224.1.
		ip a sh dev ens1f0	Shows the address information for the device ens1f0.
		ip l s ens1f0 up	Sets the link state of ens1f0 to up.
	ifconfig	ifconfig up ens9f0	Brings up the network interface ens9f0.
		ifconfig ens9f0	Displays the configuration of the network interface ens9f0.
Networking Utilities	nslookup	nslookup child-prc.intel.com	Queries DNS to obtain domain name information for child-prc.intel.com.