form feed,new line and carriage return

nicksu · 03-27-2013, 04:05 AM

Hi,can anybody help me clarify the difference between a form feed,a new line and a carriage return ?
So appreciate.

TenTenths · 03-27-2013, 04:40 AM

All terms that came from early printers:

Form Feed - Tells the printer to advance to the next page. (Back in the days when it was continuous feed paper this relied on the printer knowing the page length, AND the printer having the paper loaded properly)
New Line - Moves the print head down one line.
Carriage Return - Move the print head to the "home", (usually left) position.

colucix · 03-27-2013, 04:48 AM

Hi. The wikipedia page about Newline is quite exahustive about this topic. Please, take a look at http://en.wikipedia.org/wiki/Newline.

In a few words, different systems use different line terminators and sometimes it represents a (easily managed) problem when importing text files from Windows to Linux and viceversa. Windows uses CR + LF (that is \r\n in escape sequence notation) whereas Linux uses only LF (that is \n). Some systems provide the dos2unix and unix2dos tools to make the conversion, but there are other ways to change the newline terminators using sed, perl, awk and so on.

nicksu · 03-27-2013, 04:54 AM

Quote:

Originally Posted by colucix

Hi. The wikipedia page about Newline is quite exahustive about this topic. Please, take a look at http://en.wikipedia.org/wiki/Newline.

In a few words, different systems use different line terminators and sometimes it represents a (easily managed) problem when importing text files from Windows to Linux and viceversa. Windows uses CR + LF (that is \r\n in escape sequence notation) whereas Linux uses only LF (that is \n). Some systems provide the dos2unix and unix2dos tools to make the conversion, but there are other ways to change the newline terminators using sed, perl, awk and so on.

thank you guys

David the H. · 03-28-2013, 04:52 AM

For that matter, most of the ascii non-printing character range descends from the early days of computing, when they were used for various communication and peripheral control situations. Nowadays most of them just sit there unused, except for CR and LF, which are used as line endings, and a couple of others like null and tab.

The first 000-032 plus 177 are considered the regex [:cntrl:] character class. From man ascii:

Code:

       000   0     00    NUL '\0'
       001   1     01    SOH (start of heading)
       002   2     02    STX (start of text)
       003   3     03    ETX (end of text)
       004   4     04    EOT (end of transmission)
       005   5     05    ENQ (enquiry)
       006   6     06    ACK (acknowledge)
       007   7     07    BEL '\a' (bell)
       010   8     08    BS  '\b' (backspace)
       011   9     09    HT  '\t' (horizontal tab)
       012   10    0A    LF  '\n' (new line)
       013   11    0B    VT  '\v' (vertical tab)
       014   12    0C    FF  '\f' (form feed)
       015   13    0D    CR  '\r' (carriage ret)
       016   14    0E    SO  (shift out)
       017   15    0F    SI  (shift in)
       020   16    10    DLE (data link escape)
       021   17    11    DC1 (device control 1)
       022   18    12    DC2 (device control 2)
       023   19    13    DC3 (device control 3)
       024   20    14    DC4 (device control 4)
       025   21    15    NAK (negative ack.)
       026   22    16    SYN (synchronous idle)
       027   23    17    ETB (end of trans. blk)
       030   24    18    CAN (cancel)
       031   25    19    EM  (end of medium)
       032   26    1A    SUB (substitute)
       033   27    1B    ESC (escape)
       034   28    1C    FS  (file separator)
       035   29    1D    GS  (group separator)
       036   30    1E    RS  (record separator)
       037   31    1F    US  (unit separator)

       177   127   7F    DEL

chrism01 · 03-28-2013, 07:10 PM

The whole table is here for ref http://www.asciitable.com/