kodingwindow@kw:~$ ls
a.out  KW.class  KW.java  Desktop    Downloads	Pictures  Templates  Weekdays
kw.c   kw.csv	 kw.py	  Documents  Music	Public	  Videos

kodingwindow@kw:~$ ls -a
.	       kw.csv	  .mozilla	    .ssh
..	       KW.java	  Music		    .sudo_as_admin_successful
a.out	       kw.py	  Pictures	    Templates
.bash_history  Desktop	  .pki		    .theano
.bundle        Documents  Public	    Videos
.cache	       Downloads  .python_history   Weekdays
.config        .gnupg	  .r
kw.c	       .keras	  .Rhistory
KW.class       .local	  .rstudio-desktop

kodingwindow@kw:~$ ls -A
a.out	       kw.csv	  .keras    .python_history	       .theano
.bash_history  KW.java	  .local    .r			       Videos
.bundle        kw.py	  .mozilla  .Rhistory		       Weekdays
.cache	       Desktop	  Music     .rstudio-desktop
.config        Documents  Pictures  .ssh
kw.c	       Downloads  .pki	    .sudo_as_admin_successful
KW.class       .gnupg	  Public    Templates

kodingwindow@kw:~$ ls -1
a.out
kw.c
KW.class
kw.csv
KW.java
kw.py
Desktop
Documents
Downloads
Music
Pictures
Public
Templates
Videos
Weekdays
kodingwindow@kw:~$ 

kodingwindow@kw:~$ ls -l
total 72
-rwxr-xr-x 1 kodingwindow kodingwindow 13968 May 16  2019 a.out
-rw-r--r-- 1 kodingwindow kodingwindow    90 Jun 13 11:17 kw.c
-rw-rw-r-- 1 kodingwindow kodingwindow   411 Aug 28 14:42 KW.class
-rw-rw-r-- 1 kodingwindow kodingwindow   404 Jul 19 11:48 kw.csv
-rw-r--r-- 1 kodingwindow kodingwindow   179 Feb 24  2020 KW.java
-rw-r--r-- 1 kodingwindow kodingwindow  1608 Aug 15 12:16 kw.py
drwxr-xr-x 2 kodingwindow kodingwindow  4096 Apr  2  2019 Desktop
drwxr-xr-x 2 kodingwindow kodingwindow  4096 Aug 28 17:08 Documents
drwxr-xr-x 3 kodingwindow kodingwindow  4096 Jun 27 23:05 Downloads
drwxr-xr-x 2 kodingwindow kodingwindow  4096 Jun  6 09:06 Music
drwxr-xr-x 3 kodingwindow kodingwindow  4096 Aug 14 15:14 Pictures
drwxr-xr-x 2 kodingwindow kodingwindow  4096 Apr  2  2019 Public
drwxr-xr-x 2 kodingwindow kodingwindow  4096 Apr  2  2019 Templates
drwxr-xr-x 2 kodingwindow kodingwindow  4096 Jun  4 20:38 Videos
-rw-rw-r-- 1 kodingwindow kodingwindow    84 May 31 11:23 Weekdays

kodingwindow@kw:~$ ls -li
total 72
3408466 -rwxr-xr-x 1 kodingwindow kodingwindow 13968 May 16  2019 a.out
3408372 -rw-r--r-- 1 kodingwindow kodingwindow    90 Jun 13 11:17 kw.c
3411453 -rw-rw-r-- 1 kodingwindow kodingwindow   411 Aug 28 14:42 KW.class
3412502 -rw-rw-r-- 1 kodingwindow kodingwindow   404 Jul 19 11:48 kw.csv
3413037 -rw-r--r-- 1 kodingwindow kodingwindow   179 Feb 24  2020 KW.java
3419358 -rw-r--r-- 1 kodingwindow kodingwindow  1608 Aug 15 12:16 kw.py
3407940 drwxr-xr-x 2 kodingwindow kodingwindow  4096 Apr  2  2019 Desktop
3407944 drwxr-xr-x 2 kodingwindow kodingwindow  4096 Aug 28 17:08 Documents
3407941 drwxr-xr-x 3 kodingwindow kodingwindow  4096 Jun 27 23:05 Downloads
3407945 drwxr-xr-x 2 kodingwindow kodingwindow  4096 Jun  6 09:06 Music
3407946 drwxr-xr-x 3 kodingwindow kodingwindow  4096 Aug 14 15:14 Pictures
3407943 drwxr-xr-x 2 kodingwindow kodingwindow  4096 Apr  2  2019 Public
3407942 drwxr-xr-x 2 kodingwindow kodingwindow  4096 Apr  2  2019 Templates
3407947 drwxr-xr-x 2 kodingwindow kodingwindow  4096 Jun  4 20:38 Videos
3408355 -rw-rw-r-- 1 kodingwindow kodingwindow    84 May 31 11:23 Weekdays

kodingwindow@kw:~$ ls -i
3408466 a.out	  3413037 KW.java    3407941 Downloads	3407942 Templates
3408372 kw.c	  3419358 kw.py      3407945 Music	3407947 Videos
3411453 KW.class  3407940 Desktop    3407946 Pictures	3408355 Weekdays
3412502 kw.csv	  3407944 Documents  3407943 Public

kodingwindow@kw:~$ man ls

LS(1)                            User Commands                           LS(1)

NAME
       ls - list directory contents

SYNOPSIS
       ls [OPTION]... [FILE]...

DESCRIPTION
       List  information  about  the FILEs (the current directory by default).
       Sort entries alphabetically if none of -cftuvSUX nor --sort  is  speci‐
       fied.

       Mandatory  arguments  to  long  options are mandatory for short options
       too.

       -a, --all
              do not ignore entries starting with .

       -A, --almost-all
              do not list implied . and ..

       --author
              with -l, print the author of each file

       -b, --escape
              print C-style escapes for nongraphic characters

       --block-size=SIZE
              with  -l,  scale  sizes  by  SIZE  when  printing  them;   e.g.,
              '--block-size=M'; see SIZE format below

       -B, --ignore-backups
              do not list implied entries ending with ~
...

kodingwindow@kw:~$ info ls

Next: dir invocation,  Up: Directory listing

10.1 ‘ls’: List directory contents
==================================

The ‘ls’ program lists information about files (of any type, including
directories).  Options and file arguments can be intermixed arbitrarily,
as usual.

   For non-option command-line arguments that are directories, by
default ‘ls’ lists the contents of directories, not recursively, and
omitting files with names beginning with ‘.’.  For other non-option
arguments, by default ‘ls’ lists just the file name.  If no non-option
argument is specified, ‘ls’ operates on the current directory, acting as
if it had been invoked with a single argument of ‘.’.
...

kodingwindow@kw:~$ ls --help
Usage: ls [OPTION]... [FILE]...
List information about the FILEs (the current directory by default).
Sort entries alphabetically if none of -cftuvSUX nor --sort is specified.

Mandatory arguments to long options are mandatory for short options too.
  -a, --all                  do not ignore entries starting with .
  -A, --almost-all           do not list implied . and ..
      --author               with -l, print the author of each file
  -b, --escape               print C-style escapes for nongraphic characters
      --block-size=SIZE      with -l, scale sizes by SIZE when printing them;
                               e.g., '--block-size=M'; see SIZE format below
  -B, --ignore-backups       do not list implied entries ending with ~

...