ls.txt

ls
-l  # list/long format
-a  # include dot-files
-A  # include dot-files but not the current and parent directory
-h  # human-readable filesizes
-S  # order by size (-s shows "allocated size in blocks")
-t  # order by time
-r  # reverse order
-i  # show inode number
-Z  # print security context (AppArmor, SELinux, ..)

# get time with seconds and sub-seconds if the OS/FS supports it
$ ls --full-time
# which is shorthand for
$ ls -l --time-style=full-iso

From https://stackoverflow.com/a/24812068/126584
 In the list format, the first character, before the permissions, indicates the type of 'file':
 -  regular file
 d  directory
 l  symbolic link
 b  block special file/block device:           tends to be storage devices, buffers output, writes per block
 c  character special file/character device:   tends to be audio/graphics cards, keyboard, mouse
 C  high performance ("contiguous data") file  
 D  door (Solaris 2.5 and up)
 M  off-line ("migrated") file (Cray DMF)
 n  network special file (HP-UX)
 p  FIFO (named pipe)
 P  port (Solaris 10 and up)
 s  socketqq

# If there's a \e[38;5;201m+\e[0m sign trailing the permissions, that file/directory has extended permissions called ACLs for Access
# Control List. use \e[38;5;208mgetfacl <file>\e[0m or \e[38;5;208mls -le [file]\e[0m to view them, depending on OS.

See also: \e[38;5;208mstat\e[0m

==

# show last 10 (or given number of) modified files
# not bugfree wrt dotfiles and/or piping, not sure
lt () 
{ 
    local lines=10;
    local rf='^[0-9]+$';
    if [[ "$1" =~ $rf ]]; then
        lines=$1;
        shift;
    fi;
    if [[ -t 1 ]]; then
        command ls --color=always -lAt "$@" | head -n$((lines+1)) | tail -n$lines;
    else
        command ls -At "$@" | head -n$lines;
    fi
}