Redhat - Day1 (Basic Linux Commands).txt

//File navigation in Command line

command    description	
pwd    	   present working directory

cd         change directory | 1. cd .. to go parent directory | 2. cd [directory_name] to change directory

ls         lists directory contents of files and directories

	option	description
ls 	-a	list all files including hidden file starting with '.'
ls 	-i	list file's inode index number
ls 	-l	list with long format - show permissions
ls 	-la	list long format including hidden files
ls 	-lh	list long format with readable file size
ls 	-ls	list with long format with file size
ls 	-r	list in reverse order
ls 	-s	list file size
ls 	-S	sort by file size
ls 	-lt	time-based list
ls 	-Z	The system_u,object_r,var_t and s0 output demonstrates the current SELinux contexts of the noted files.

//Basic commands to manage file 

cat     means catenate,It reads and write data from files,display the contents of a file at the command line.

>       output redirect used to create file,(can use it without cat to create file),redirect the output.
>>	append the content next in file

 	Displaying text files  ----- cat [file_name]
	Concatenate text files ----- cat [file1] [file2]
	
cat file1.txt > file2.txt    		reads the content of file1.txt and '>' redirect output to file2.txt [overwrite if file exist] 

cat file1.txt >> file2.txt   		reads the content of file2.txt and '>>' append data to file2.txt
cat file1.txt file2.txt > file3.txt     reads both file1.txt and file2.txt data and overwrite it to file3.txt
cat file1.txt file2.txt >> file3.txt    reads both file1.txt and file2.txt data and append it to file3.txt