find(1) -maxdepth 1 -type d -a ! -name '.' -exec basename(1) {} \; | sort(1) | tail(1) -n 3
search for files in a directory hierarchy
-maxdepth levels
       Descend  at  most  levels  (a  non-negative  integer) levels of directories below the command line
       arguments.  -maxdepth 0
        means only apply the tests and actions to the command line arguments.
-type c
       File is of type c:

       b      block (buffered) special

       c      character (unbuffered) special

       d      directory

       p      named pipe (FIFO)

       f      regular file

       l      symbolic link; this is never true if the -L option or the  -follow  option  is  in  effect,
              unless the symbolic link is broken.  If you want to search for symbolic links when -L is in
              effect, use -xtype.

       s      socket

       D      door (Solaris)
expr1 expr2
       Two expressions in a row are taken to be joined with an implied "and"; expr2 is not  evaluated  if
       expr1 is false.

expr1 -a expr2
       Same as expr1 expr2.

expr1 -and expr2
       Same as expr1 expr2, but not POSIX compliant.
find [-H] [-L] [-P] [-D debugopts] [-Olevel] [path...] [expression]
-name pattern
       Base of file name (the path with the leading directories removed) matches shell  pattern  pattern.
       The  metacharacters  (`*',  `?',  and  `[]')  match a `.' at the start of the base name (this is a
       change in findutils-4.2.2; see section STANDARDS CONFORMANCE below).  To ignore  a  directory  and
       the  files  under  it,  use  -prune;  see  an example in the description of -path.  Braces are not
       recognised as being special, despite the fact that some shells including Bash imbue braces with  a
       special  meaning  in  shell  patterns.   The  filename  matching  is performed with the use of the
       fnmatch(3) library function.   Don't forget to enclose the pattern in quotes in order  to  protect
       it from expansion by the shell.
-exec command ;
       Execute  command;  true  if 0 status is returned.  All following arguments to find are taken to be
       arguments to the command until an argument consisting of `;' is encountered.  The string  `{}'  is
       replaced  by  the  current  file name being processed everywhere it occurs in the arguments to the
       command, not just in arguments where it is alone, as in some versions  of  find.   Both  of  these
       constructions  might  need  to be escaped (with a `\') or quoted to protect them from expansion by
       the shell.  See the EXAMPLES section for examples of the use of the -exec option.   The  specified
       command  is  run  once  for each matched file.  The command is executed in the starting directory.
       There are unavoidable security problems surrounding use of the -exec action; you  should  use  the
       -execdir option instead.

-exec command {} +
       This variant of the -exec action runs the specified command on the selected files, but the command
       line is built by appending each selected file name at the end; the total number of invocations  of
       the command will be much less than the number of matched files.  The command line is built in much
       the same way that xargs builds its command lines.  Only one instance of `{}' is allowed within the
       command.  The command is executed in the starting directory.
strip directory and suffix from filenames
Pipelines
    A  pipeline is a sequence of one or more commands separated by one of the control operators | or |&.  The
    format for a pipeline is:

           [time [-p]] [ ! ] command [ [||&] command2 ... ]

    The standard output of command is connected  via  a  pipe  to  the  standard  input  of  command2.   This
    connection  is performed before any redirections specified by the command (see REDIRECTION below).  If |&
    is used, the standard error of command is connected to command2's standard input through the pipe; it  is
    shorthand  for  2>&1  |.   This  implicit  redirection  of  the  standard  error  is  performed after any
    redirections specified by the command.

    The return status of a pipeline is the exit status of the last command, unless  the  pipefail  option  is
    enabled.   If  pipefail  is  enabled,  the  pipeline's return status is the value of the last (rightmost)
    command to exit with a non-zero status, or zero if all commands exit successfully.  If the reserved  word
    !   precedes  a  pipeline, the exit status of that pipeline is the logical negation of the exit status as
    described above.  The shell waits for all commands in the pipeline to terminate before returning a value.

    If the time reserved word precedes a pipeline, the elapsed as well as user and system  time  consumed  by
    its execution are reported when the pipeline terminates.  The -p option changes the output format to that
    specified by POSIX.  When the shell is in posix mode, it does not recognize time as a  reserved  word  if
    the  next  token begins with a `-'.  The TIMEFORMAT variable may be set to a format string that specifies
    how the timing information should be displayed; see the description of TIMEFORMAT under  Shell  Variables
    below.

    When the shell is in posix mode, time may be followed by a newline.  In this case, the shell displays the
    total user and system time consumed by the shell and its children.  The TIMEFORMAT variable may  be  used
    to specify the format of the time information.

    Each command in a pipeline is executed as a separate process (i.e., in a subshell).
sort lines of text files
output the last part of files
-n, --lines=K
       output  the  last  K lines, instead of the last 10; or use -n +K to output lines starting with the
       Kth
source manpages: findbasenamesorttail