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Linux User Level Command

Here is the compiled list of basic Linux user commands required for working on Linux platform.

Listing of files and folders

Optional Arguments
-a, --all
    do not hide entries starting with .
    use a long listing format
-r, --reverse
    reverse order while sorting
-s, --size
    print size of each file, in blocks
    list entries by lines instead of by columns
Copy files and directories

Optional Arguments
f, --force
   if an existing destination file cannot be opened, remove it and try again
-i, --interactive
    prompt before overwrite
-l, --link
   link files instead of copying
-R, -r, --recursive
   copy directories recursively
v, --verbose
   explain what is being done
-x, --one-file-system
   stay on this file system
Make a directory if it does not already exist

Remove files and folders. By default, it does not remove folders

Optional Arguments
-f, --force
    ignore nonexistent files, never prompt
-i, --interactive
    prompt before any removal
-r, -R, --recursive
    remove the contents of directories recursively
-v, --verbose
    explain what is being done
rm -rf
Removes folders and files in recursively without asking confirmation from user

Change directory

Show the name of the current working directory

Creates links to a file. Useful for creating alias for long file names

Optional Arguments
-i, --interactive
    prompt whether to remove destinations
-s, --symbolic
    make symbolic links instead of hard links

Moves or renames file.

Optional Arguments
-f, --force
    do not prompt before overwriting
-i, --interactive
    prompt before overwrite equivalent

Deletes directories
Change permission for file or directory. There are three types of access:
1. read
2. write
3. execute
Each file belongs to a specific user and group. Access to the files is controlled by user, group, and what is called other.
The format is `[ugo][[+-=][rwx]
The operator `+' causes the permissions selected to be added to the existing permissions . `-' causes permissions to be removed; and `=' causes them to be the only permissions that the file has.
The letters `rwx' select the new permissions for the affected users: read (r), write (w), execute (or access for directories) (x).

Concatenate the files and sends the file to standard output

Optional Arguments
-n, --number
    number all output lines
-s, --squeeze-blank
    never more than one single blank line

Show the amount of disk space used on each mounted files system.
Print disk usage (as the number of 1 KB blocks used by each named directory and its subdirectories; default is the current directory).
-a, --all
    write counts for all files, not just directories
-B, --block-size=SIZE use SIZE-byte blocks
-b, --bytes
    print size in bytes
-c, --total
    produce a grand total

Searches for files in the directory hierarchy

Searches for files in the directory hierarchy. Locate command works faster than find command

Searches for regular expression or a pattern in file. By defaults prints the matching lines
$ grep "Hello" file1

This command is a manual for Linux commands. Provides help for any command in Linux. To find the usage and all the options available with that command type man command

Change owner, change the user and/or group ownership of each given file to a new Owner.
Create tape archives and add or extract files. Basically used to compress and decompress files

Optional Arguments
-r, --append
    append files to the end of an archive
-t, --list
    list the contents of an archive
-u, --update
    only append files that are newer than copy in archive
-x, --extract, --get
    extract files from an archive
-v, --verbose
    verbosely list files processed
-w, --interactive, --confirmation
    ask for confirmation for every action
-z, --gzip, --ungzip
    filter the archive through gzip

Creating a tar file:
tar -cvf file.tar filetobetarred.txt
It would create a tar named file.tar in the directory you currently are in.

tar -cvf mydir.tar mydir/
In the above example command the system would create a tar file named mydir.tar in the directory you currently are in.

Extracting the files from a tar file:
tar -xvf testfile.tar
In the above example command the system would uncompress (untar) the testfile.tar file in the current directory.

gzip, gunzip, zcat - compress or expand files
Gzip reduces the size of the named files using Lempel-Ziv coding (LZ77). Whenever possible, each file is replaced by one with the extension .gz, while keeping the same ownership modes, access and modification times.
Compressed files can be restored to their original form using gzip -d or gunzip

Find and Replace in vi editor
Search and Replace a word in whole file
Example ": %s/Test/Text/g" - For all lines in a file, find string "Test" and replace with string "Text" for each instance in a file. Run the command in Esc mode in vi editor.