search for files in a directory hierarchy

find [-H] [-L] [-P] [-D debugopts] [-Olevel] [path...] [expression]

-not expr
       Same as ! expr, but not POSIX compliant.

-path pattern
       File  name  matches  shell pattern pattern.  The metacharacters do not treat `/' or `.' specially;
       so, for example,
                 find . -path "./sr*sc"
       will print an entry for a directory called `./src/misc'  (if  one  exists).   To  ignore  a  whole
       directory  tree, use -prune rather than checking every file in the tree.  For example, to skip the
       directory `src/emacs' and all files and directories under it, and print the  names  of  the  other
       files found, do something like this:
                 find . -path ./src/emacs -prune -o -print
       Note  that  the  pattern match test applies to the whole file name, starting from one of the start
       points named on the command line.  It would only make sense to use an absolute path name  here  if
       the  relevant start point is also an absolute path.  This means that this command will never match
       anything:
                 find bar -path /foo/bar/myfile -print
       The predicate -path is also supported by HP-UX find and will be in a forthcoming  version  of  the
       POSIX standard.

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).

print lines matching a pattern

-i, --ignore-case
       Ignore case distinctions in both the PATTERN and the input files.  (-i is specified by POSIX.)

-P, --perl-regexp
       Interpret PATTERN as a Perl regular expression (PCRE, see below).  This is highly experimental and
       grep -P may warn of unimplemented features.

grep searches the named input FILEs (or standard input if no files are named, or if a single hyphen-minus
(-) is given as file name) for lines containing a match to the given PATTERN.  By  default,  grep  prints
the matching lines.

construct argument lists and invoke utility

-n  number
       Invoke utility using as many standard input arguments  as  possible,  up  to  number  (a  positive
       decimal integer) arguments maximum. Fewer arguments shall be used if:

        * The  command line length accumulated exceeds the size specified by the -s option (or {LINE_MAX}
          if there is no -s option).

        * The last iteration has fewer than number, but not zero, operands remaining.

-I  replstr
       Insert mode: utility is executed for each line from standard input, taking the entire  line  as  a
       single  argument,  inserting  it  in  arguments  for each occurrence of replstr. A maximum of five
       arguments in arguments can each contain one or more instances of  replstr.  Any  <blank>s  at  the
       beginning  of each line shall be ignored. Constructed arguments cannot grow larger than 255 bytes.
       Option -x shall be forced on.

Commands separated  by  a ; are executed sequentially; the shell waits for each command to terminate in turn.  The
return status is the exit status of the last command executed.