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LS
The command “ls” displays the list of all directories, folder, and files present in the current directory.
LS - LTR
The above-mentioned command displays the name of directories, folders, files with their respective owner name, group’s name, and rights your user has over these.
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ls
ls -ltr
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/$ ls
bin dev lib libx32 mnt root snap sys usr
boot etc lib32 lost+found opt run srv tim var
cdrom home lib64 media proc sbin swapfile tmp
/$ ls -ltr
total 2097256
drwxr-xr-x 2 root root 4096 Feb 9 2021 mnt
drwxr-xr-x 15 root root 4096 Feb 9 2021 var
drwx------ 2 root root 16384 Feb 11 2022 lost+found
lrwxrwxrwx 1 root root 8 Feb 11 2022 sbin -> usr/sbin
lrwxrwxrwx 1 root root 10 Feb 11 2022 libx32 -> usr/libx32
lrwxrwxrwx 1 root root 9 Feb 11 2022 lib64 -> usr/lib64
lrwxrwxrwx 1 root root 9 Feb 11 2022 lib32 -> usr/lib32
lrwxrwxrwx 1 root root 7 Feb 11 2022 lib -> usr/lib
lrwxrwxrwx 1 root root 7 Feb 11 2022 bin -> usr/bin
drwxrwxr-x 2 root root 4096 Feb 11 2022 cdrom
drwx------ 10 root root 4096 Feb 12 2022 tim
-rw------- 1 root root 2147487744 Aug 9 2022 swapfile
drwxr-xr-x 5 root root 4096 Aug 14 2022 home
drwxr-xr-x 14 root root 4096 Oct 22 14:08 usr
drwxrwxrwx 7 root root 4096 Nov 26 04:18 media
drwxrwxrwx 13 root root 4096 Jan 7 21:59 opt
drwxr-xr-x 2 root root 4096 Feb 5 07:19 srv
dr-xr-xr-x 13 root root 0 Feb 7 23:41 sys
dr-xr-xr-x 549 root root 0 Feb 7 23:41 proc
drwx------ 12 root root 4096 Feb 8 04:25 root
drwxr-xr-x 20 root root 5120 Feb 17 23:04 dev
drwxr-xr-x 28 root root 4096 Feb 21 23:36 snap
drwxr-xr-x 168 root root 12288 Mar 1 06:24 etc
drwxr-xr-x 5 root root 4096 Mar 2 06:51 boot
drwxr-xr-x 46 root root 1500 Mar 2 20:11 run
drwxrwxrwt 32 root root 20480 Mar 2 21:06 tmp
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MKDIR
The command “mkdir” allows users to create directories/folders in the system. The user running this command must have suitable rights over the parent directory to create a directory or they will receive an error.
Syntax: mkdir New_Directory’s_Name
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mkdir NewDirectory
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~$ mkdir poopoo
~$
~$ ls
Android Pictures
AppImages poopoo
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RMDIR
The command “rmdir” allows users to remove directories/folders from the system. The user running this command must have suitable rights over the parent directory to remove a directory AND the directory must not have any files or sub-directories within it or you will receive an error.
Syntax: rmdir Directory’s_Name
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rmdir DirectoryName
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~$ rmdir poopoo
rmdir: failed to remove 'poopoo': Directory not empty
# Could not delete directory
# "poopoo" because it is not
# empty
~$ rm poopoo
rm: cannot remove 'poopoo': Is a directory
# Could not remove "poopoo"
# because it is not a file
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RM
The command “rm” is used to remove files from a directory.
RM -RF
Permanently deletes the specified directory and ALL files and sub-directories beneath the specified directory.
Be VERY careful using this command as you can inadvertently delete your whole drive!
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rm filename
rm -rf /path/to/dir/name
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# Listing shows poopoo.txt
# file exists under
# direcotry "poopoo"
~/poopoo$ ls
poopoo.txt
~/poopoo$ rm poopoo.txt
# listing now shows
# poopoo.txt has been
# removed (deleted)
# from directory "poopoo"
~/poopoo$ ls
~/poopoo$
# Directory "poopoo" exists
# in the listing below
~$ ls
Android Pictures
AppImages poopoo
Audio Public
~$ rm -rf poopoo
~$
# Successfully removed
# "poopoo" directory
# and all its contents
# as can be seen in the
# listing below
~$ ls
Android Parkitect
AppImages Pictures
Audio Public
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MV
The command “mv” is used for two purposes
- To move files or directories from one path to another path in the system.
- To rename a file or folder.
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mv Source_File_name Destination_File_Name
mv File_name New_name_for_file
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CP
The command “cp” is used to copy data from a source file to the destination file. Its function is almost like the command “mv”. The only difference is by using the command “cp” the source file is not removed from the directory after its data is moved to the destination file.
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cp source_file_name destination_file_name
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TOUCH
Creates an empty file at the specified path with the specified name.
Useful for creating a blank file you intend to edit with a CLI editor, such as VIM or NANO.
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touch /path/name/filename.ext
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~$ ls doc.txt
ls: cannot access 'doc.txt': No such file or directory
~$ touch /home/tim/doc.txt
~$ ls doc.txt
doc.txt
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CAT
The command “cat” is a reverse of the command “tac”. It is used to display each line of the file starting from the first row and finishing on its last row.
This command is more frequently used than “tac”.
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cat file_name
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ECHO
The command “echo” used to display any expression that is passed as an argument.
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echo expression_to_be_displayed
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~/poopoo$ echo something-poopoo
something-poopoo
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GREP
The command “grep” is used to search for a text in the specified file/folder.
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grep “expression_to_be_Searched” file_name_to_search_in
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ZIP
The command “zip” is used to compress one or more files and store them in a new file with .zip extension.
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zip new_zip_file_name.zip
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~/poopoo$ zip files.zip file1.txt file2.txt file3.txt
adding: file1.txt (stored 0%)
adding: file2.txt (stored 0%)
adding: file3.txt (stored 0%)
~/poopoo$ ls
file1.txt file2.txt file3.txt files.zip
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UNZIP
The command “unzip” is used to decompress a .zip file and extract all the files within to current directory.
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unzip zip_file_name.zip
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~/poopoo$ unzip files.zip
Archive: files.zip
replace file1.txt? [y]es, [n]o, [A]ll, [N]one, [r]ename: A
extracting: file1.txt
extracting: file2.txt
extracting: file3.txt
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SUDO
Sudo stands for SuperUser DO and is used to access restricted files and operations. By default, Linux restricts access to certain parts of the system preventing sensitive files from being compromised.
The sudo command temporarily elevates privileges allowing users to complete sensitive tasks without logging in as the root user.
sudo -i elevates the user to root for the remainder of the session rather than a command by command basis.
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sudo some-command
sudo -i
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# No directory called "peepee"
# exists
$ ls
bin dev lib libx32 mnt root snap sys usr
boot etc lib32 lost+found opt run srv tim var
cdrom home lib64 media proc sbin swapfile tmp
# Attempt to make directory
# "peepee" as a noraml user
# fails because I'm
# trying to make the
# directory in a path I
# don't have rights to
$ mkdir peepee
mkdir: cannot create directory ‘peepee’: Permission denied
# using SUDO to temporarily
# elevate my privileges, I
# can now create the
# directory "peepee"
# in the path as can be seen
# in the listing below:
$ sudo mkdir peepee
[sudo] password for tim:
$ ls
bin dev lib libx32 mnt proc sbin swapfile tmp
boot etc lib32 lost+found opt root snap sys usr
cdrom home lib64 media peepee run srv tim var
~/poopoo$ sudo -i
[sudo] password for tim:
~#
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