shell more less cat

cat        连续显示、查看文件内容
more        分页查看文件内容
less 分页可控制查看文件内容

通俗点说：
cat一次性把文件内容全部显示出来，管你看不看得清，显示完了cat命令就返回了，不能进行交互式操作，适合察看内容短小、不超过一屏的文件；
more比cat强大一点，支持分页显示，你可以ctrl+B ctrl+F .....上下滚屏，但是不支持像shift+G（跳到文件尾）这种操作；
less比more更强大一点，支持各种命令，随便翻页、跳转、查找.....想怎么看，就怎么看，爱怎么看，就怎么看。
                   SUMMARY OF LESS COMMANDS

      Commands marked with * may be preceded by a number, N.

      Notes in parentheses indicate the behavior if N is given.

  h  H                 Display this help.

  q  :q  Q  :Q  ZZ     Exit.

---------------------------------------------------------------------------

                           MOVING

  e  ^E  j  ^N  CR  *  Forward  one line   (or N lines).

  y  ^Y  k  ^K  ^P  *  Backward one line   (or N lines).

  f  ^F  ^V  SPACE  *  Forward  one window (or N lines).

  b  ^B  ESC-v      *  Backward one window (or N lines).

  z                 *  Forward  one window (and set window to N).

  w                 *  Backward one window (and set window to N).

  ESC-SPACE         *  Forward  one window, but don't stop at end-of-file.

  d  ^D             *  Forward  one half-window (and set half-window to N).

  u  ^U             *  Backward one half-window (and set half-window to N).

  ESC-)  RightArrow *  Left  one half screen width (or N positions).

  ESC-(  LeftArrow  *  Right one half screen width (or N positions).

  F                    Forward forever; like "tail -f".

  r  ^R  ^L            Repaint screen.

  R                    Repaint screen, discarding buffered input.

        ---------------------------------------------------

        Default "window" is the screen height.

        Default "half-window" is half of the screen height.

---------------------------------------------------------------------------

                          SEARCHING

  /pattern          *  Search forward for (N-th) matching line.

  ?pattern          *  Search backward for (N-th) matching line.

  n                 *  Repeat previous search (for N-th occurrence).

  N                 *  Repeat previous search in reverse direction.

  ESC-n             *  Repeat previous search, spanning files.

  ESC-N             *  Repeat previous search, reverse dir. & spanning files.

  ESC-u                Undo (toggle) search highlighting.

        ---------------------------------------------------

        Search patterns may be modified by one or more of:

        ^N or !  Search for NON-matching lines.

        ^E or *  Search multiple files (pass thru END OF FILE).

        ^F or @  Start search at FIRST file (for /) or last file (for ?).

        ^K       Highlight matches, but don't move (KEEP position).

        ^R       Don't use REGULAR EXPRESSIONS.

---------------------------------------------------------------------------

                           JUMPING

  g  <  ESC-<       *  Go to first line in file (or line N).

  G  >  ESC->       *  Go to last line in file (or line N).

  p  %              *  Go to beginning of file (or N percent into file).

  t                 *  Go to the (N-th) next tag.

  T                 *  Go to the (N-th) previous tag.

  {  (  [           *  Find close bracket } ) ].

  }  )  ]           *  Find open bracket { ( [.

  ESC-^F <c1> <c2>  *  Find close bracket <c2>.

  ESC-^B <c1> <c2>  *  Find open bracket <c1>
        ---------------------------------------------------

        Each "find close bracket" command goes forward to the close bracket
          matching the (N-th) open bracket in the top line.

        Each "find open bracket" command goes backward to the open bracket
          matching the (N-th) close bracket in the bottom line.

  m<letter>            Mark the current position with <letter>.

  '<letter>            Go to a previously marked position.

  ''                   Go to the previous position.

  ^X^X                 Same as '.

        ---------------------------------------------------

        A mark is any upper-case or lower-case letter.

        Certain marks are predefined:

             ^  means  beginning of the file

             $  means  end of the file

---------------------------------------------------------------------------

                        CHANGING FILES

  :e [file]            Examine a new file.

  ^X^V                 Same as :e.

  :n                *  Examine the (N-th) next file from the command line.

  :p                *  Examine the (N-th) previous file from the command line.

  :x                *  Examine the first (or N-th) file from the command line.

  :d                   Delete the current file from the command line list.

  =  ^G  :f            Print current file name.

---------------------------------------------------------------------------

                    MISCELLANEOUS COMMANDS

  -<flag>              Toggle a command line option [see OPTIONS below].

  --<name>             Toggle a command line option, by name.

  _<flag>              Display the setting of a command line option.

  __<name>             Display the setting of an option, by name.

  +cmd                 Execute the less cmd each time a new file is examined.

  !command             Execute the shell command with $SHELL.

  |Xcommand            Pipe file between current pos & mark X to shell command.

  v                    Edit the current file with $VISUAL or $EDITOR.

  V                    Print version number of "less".

---------------------------------------------------------------------------

                           OPTIONS

        Most options may be changed either on the command line,

        or from within less by using the - or -- command.

        Options may be given in one of two forms: either a single

        character preceded by a -, or a name preceeded by --.

  -?  ........  --help

                  Display help (from command line).

  -a  ........  --search-skip-screen

                  Forward search skips current screen.

  -b [N]  ....  --buffers=[N]

                  Number of buffers.

  -B  ........  --auto-buffers

                  Don't automatically allocate buffers for pipes.

  -c  -C  ....  --clear-screen  --CLEAR-SCREEN

                  Repaint by scrolling/clearing.

  -d  ........  --dumb

                  Dumb terminal.

  -D [xn.n]  .  --color=xn.n

                  Set screen colors. (MS-DOS only)

  -e  -E  ....  --quit-at-eof  --QUIT-AT-EOF

                  Quit at end of file.

  -f  ........  --force

                  Force open non-regular files.

  -F  ........  --quit-if-one-screen

                  Quit if entire file fits on first screen.

  -g  ........  --hilite-search

                  Highlight only last match for searches.

  -G  ........  --HILITE-SEARCH

                  Don't highlight any matches for searches.

  -h [N]  ....  --max-back-scroll=[N]

                  Backward scroll limit.

  -i  ........  --ignore-case

                  Ignore case in searches that do not contain uppercase.

  -I  ........  --IGNORE-CASE

                  Ignore case in all searches.

  -j [N]  ....  --jump-target=[N]

                  Screen position of target lines.

  -J  ........  --status-column

                  Display a status column at left edge of screen.

  -k [file]  .  --lesskey-file=[file]

                  Use a lesskey file.

  -L  ........  --no-lessopen

                  Ignore the LESSOPEN environment variable.

  -m  -M  ....  --long-prompt  --LONG-PROMPT

                  Set prompt style.

  -n  -N  ....  --line-numbers  --LINE-NUMBERS

                  Use line numbers.

  -o [file]  .  --log-file=[file]

                  Copy to log file (standard input only).

  -O [file]  .  --LOG-FILE=[file]

                  Copy to log file (unconditionally overwrite).

  -p [pattern]  --pattern=[pattern]

                  Start at pattern (from command line).

  -P [prompt]   --prompt=[prompt]

                  Define new prompt.

  -q  -Q  ....  --quiet  --QUIET  --silent --SILENT

                  Quiet the terminal bell.

  -r  -R  ....  --raw-control-chars  --RAW-CONTROL-CHARS

                  Output "raw" control characters.

  -s  ........  --squeeze-blank-lines

                  Squeeze multiple blank lines.

  -S  ........  --chop-long-lines

                  Chop long lines.

  -t [tag]  ..  --tag=[tag]

                  Find a tag.

  -T [tagsfile] --tag-file=[tagsfile]

                  Use an alternate tags file.

  -u  -U  ....  --underline-special  --UNDERLINE-SPECIAL

                  Change handling of backspaces.

  -V  ........  --version

                  Display the version number of "less".

  -w  ........  --hilite-unread

                  Highlight first new line after forward-screen.

  -W  ........  --HILITE-UNREAD

                  Highlight first new line after any forward movement.

  -x [N[,...]]  --tabs=[N[,...]]

                  Set tab stops.

  -X  ........  --no-init

                  Don't use termcap init/deinit strings.

                --no-keypad

                  Don't use termcap keypad init/deinit strings.

  -y [N]  ....  --max-forw-scroll=[N]

                  Forward scroll limit.

  -z [N]  ....  --window=[N]

                  Set size of window.

  -" [c[c]]  .  --quotes=[c[c]]

                  Set shell quote characters.

  -~  ........  --tilde

                  Don't display tildes after end of file.

  -# [N]  ....  --shift=[N]

                  Horizontal scroll amount (0 = one half screen width)

---------------------------------------------------------------------------

                          LINE EDITING

        These keys can be used to edit text being entered
        on the "command line" at the bottom of the screen.

RightArrow                       ESC-l     Move cursor right one character.

LeftArrow                        ESC-h     Move cursor left one character.

CNTL-RightArrow  ESC-RightArrow  ESC-w     Move cursor right one word.

CNTL-LeftArrow   ESC-LeftArrow   ESC-b     Move cursor left one word.

HOME                             ESC-0     Move cursor to start of line.

END                              ESC-$     Move cursor to end of line.

BACKSPACE                                  Delete char to left of cursor.

DELETE                           ESC-x     Delete char under cursor.

CNTL-BACKSPACE   ESC-BACKSPACE             Delete word to left of cursor.

CNTL-DELETE      ESC-DELETE      ESC-X     Delete word under cursor.

CNTL-U           ESC (MS-DOS only)         Delete entire line.

UpArrow                          ESC-k     Retrieve previous command line.

DownArrow                        ESC-j     Retrieve next command line.

TAB                                        Complete filename & cycle.

SHIFT-TAB                        ESC-TAB   Complete filename & reverse cycle.

CNTL-L                                     Complete filename, list all.

HELP -- END -- Press g to see it again, or q when done