The difference between cat, more, and less commands in Linux

It is well known that Linux commands Cat, more, and less to view the contents of a file, the main differences are:
Cat is a one-time display of the entire content of the file, you can also connect a number of files to display, it is often used in conjunction with redirection symbols, applicable to the situation of less file content;
More and less is typically used to display content that has more than one screen of file content and provides the ability to turn pages. More powerful than cat, provides pagination display features, less than more powerful, provide page flipping, jump, find and other commands. And more and less support: Display the next page with a space, press B to display the previous page. These 3 commands are described in detail below.

Cat

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2. 1. Command format
4. Cat [Options] ... [File] ...
6. 2. Command function
8. Output the [file] or standard input combination to the standard output.
10. <strong>cat has three major functions:
12. 1). show entire file at once: Cat filename
14. 2). Create a file from the keyboard: cat > FileName can only create new files and cannot edit existing files.
16. 3). Merge several files into one file: Cat file1 file2 > file</strong>
18. 3. List of common parameters
20. -A,--show-all equals-vet
22. <strong>-B,--number-nonblank for non-null output line numbering </strong>
24. -E equals-ve
26. -E,--show-ends displays "$" at the end of each line
28. <strong>-N,--number all line numbering for the output </strong>
30. -S,--squeeze-blank does not output multiple lines of blank lines
32. -T vs.-VT equivalence
34. -T,--show-tabs to display the ^i character as a
36. -U (ignored)
38. -V,--show-nonprinting uses ^ and M-references, except LFD and TAB
40. --HELP Display this help message and exit <strong>
42. </strong>--version display version information and exit

4. Example

Number of non-null output lines

Output All line numbers:

More

The more command, which functions like cat, the Cat command is the entire contents of the file displayed on the screen from top to bottom. More will be a page-by-page display to facilitate users to read pages, and the most basic instruction is to press the blank key (space) on the next page, press the B key will be back to a page, but also the function of the search string. The more command reads the file backwards from the front, so it loads the entire file at startup.

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2. 1. Command format
4. more [-DLFPCSU] [-num] [+/pattern] [+linenum] [File ...]
6. 2. Command function
8. The more commands and the cat function are the same view of the contents of the file, but the difference is that more can be viewed by the page to view the contents of the file, but also support the function of direct jump.
10. 3. List of common parameters
12. -num number of rows displayed at one time
14. -D displays friendly tips at the bottom of each screen
16. -L ignores Ctrl+l (page break). If this option is not given, the more command pauses the display after displaying a line containing ctrl+l characters and waits for the command to be received.
18. -F Number of rows, in actual number of rows, rather than lines after word wrap (some single-line words that are too long will be extended to two or more lines)
20. -P Displays the screen before the next screen.
22. -C clear the screen from the top and then display.
24. -s file is compressed into a blank line in a contiguous blank line.
26. -U does not display underscores
28. +/first searches for strings and then displays them from the string
30. +num starting from Num line

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1. 4. Common Operation commands

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1. Enter down n rows, which need to be defined. Default is 1 rows
2. CTRL+F Scroll down one screen
3. Space bar scroll down one screen
4. Ctrl+b Back to previous screen
5. = Output the line number of the current line
6. : F output File name and line number of the current line
7. V Call VI Editor
8. command to invoke the shell and execute the command
9. Q Exit More

Less

The less tool is also a tool for paging through files or other output, which is a very powerful tool for Linux to view the contents of a file. The usage of less is more resilient than more. In more, we have no way to turn front, can only look back, but if use less, you can use [PageUp] [PageDown] and other key functions to go to look at the file, more easily used to view the contents of a file! In addition, in less you can have more search function, not only to search down, but also to search upward.

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2. 1. Command format:
4. Less [parameter] file
6. 2. Command function:
8. Less is similar to more, but you can browse files at will with less, and more can only move forward, but not backwards, and no will load the entire file before viewing it.
10. 3. Command parameters:
12. -B < buffer size > Set buffer size
14. -e When the file display is finished, automatically leave
16. -F forcing special files to be opened, such as peripheral code, directories, and binaries
18. -G only flags the last keyword searched
20. -I ignores case when searching
22. -m shows a percentage similar to the more command
24. <strong>-n Show line numbers for each line </strong>
26. -o < file name > save less output in the specified file
28. -Q does not use warning tones
30. -S displays a row of continuous empty behavior
32. -S line too long will be out of the partial discard
34. -X < number > Displays the "tab" key as a specified number space
36. <strong>/string: Search down the function of "string"
38. String: Search up the function of "string" </strong>
40. N: Repeat the previous search (with/or?). About
42. N: Reverse repeats the previous search (and/or?) About
44. <strong>b back one page
46. D Turn back half page </strong>
48. H Display Help interface
50. Q Exit less command
52. U scroll forward Half page
54. Y Scrolls forward one line
56. <strong> SPACEBAR Scrolls one page
58. Enter a line </strong> scroll

Reference:

Http://www.cnblogs.com/peida/archive/2012/10/30/2746968.html

Http://www.cnblogs.com/peida/archive/2012/11/02/2750588.html

Http://www.cnblogs.com/peida/archive/2012/11/05/2754477.html

The difference between cat, more, and less commands in Linux