No newline at end of file

Question

When doing a git diff it says  No newline at end of file    Ok  there is no newline at end of file  What s the big deal   What s the significance of the message and what s it trying to tell us

User · Answer

This actually does cause a problem because line endings are automatically modified dirtying files without making any changes to them   See this post for resolution   git replacing LF with CRLF

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The reason this convention came into practice is because on UNIX-like operating systems a newline character is treated as a line terminator and or message boundary  this includes piping between processes  line buffering  etc     Consider  for example  that a file with just a newline character is treated as a single  empty line  Conversely  a file with a length of zero bytes is actually an empty file with zero lines  This can be confirmed according to the wc -l command   Altogether  this behavior is reasonable because there would be no other way to distinguish between an empty text file versus a text file with a single empty line if the  n character was merely a line-separator rather than a line-terminator  Thus  valid text files should always end with a newline character  The only exception is if the text file is intended to be empty  no lines

User · Answer

It s not just bad style  it can lead to unexpected behavior when using other tools on the file   Here is test txt   first line second line   There is no newline character on the last line  Let s see how many lines are in the file     wc -l test txt 1 test txt   Maybe that s what you want  but in most cases you d probably expect there to be 2 lines in the file   Also  if you wanted to combine files it may not behave the way you d expect     cat test txt test txt first line second linefirst line second line   Finally  it would make your diffs slightly more noisy if you were to add a new line  If you added a third line  it would show an edit to the second line as well as the new addition

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It indicates that you do not have a newline  usually   n   aka CR or CRLF  at the end of file   That is  simply speaking  the last byte  or bytes if you re on Windows  in the file is not a newline   The message is displayed because otherwise there is no way to tell the difference between a file where there is a newline at the end and one where is not  Diff has to output a newline anyway  or the result would be harder to read or process automatically   Note that it is a good style to always put the newline as a last character if it is allowed by the file format  Furthermore  for example  for C and C   header files it is required by the language standard

User · Answer

Source files are often concatenated by tools  C  C    header files  Javascript  bundlers   If you omit the newline character  you could introduce nasty bugs  where the last line of one source is concatenated with the first line of the next source file    Hopefully all the source code concat tools out there insert a newline between concatenated files anyway but that doesn t always seem to be the case   The crux of the issue is - in most languages  newlines have semantic meaning and end-of-file is not a language defined alternative for the newline character   So you ought to terminate every statement expression with a newline character -- including the last one

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ubuntu  gt  vi source cpp   set binary noeol

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There is one thing that I don t see in previous responses  Warning about no end-of-line could be a warning when a portion of a file has been truncated  It could be a symptom of missing data

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The only reason is that Unix historically had a convention of all human-readable text files ending in a newline  At the time  this avoided extra processing when displaying or joining text files  and avoided treating text files differently to files containing other kinds of data  eg raw binary data which isn t human-readable    Because of this convention  many tools from that era expect the ending newline  including text editors  diffing tools  and other text processing tools  Mac OS X was built on BSD Unix  and Linux was developed to be Unix-compatible  so both operating systems have inherited the same convention  behaviour and tools   Windows wasn t developed to be Unix-compatible  so it doesn t have the same convention  and most Windows software will deal just fine with no trailing newline   But  since Git was developed for Linux first  and a lot of open-source software is built on Unix-compatible systems like Linux  Mac OS X  FreeBSD  etc  most open-source communities and their tools  including programming languages  continue to follow these conventions   There are technical reasons which made sense in 1971  but in this era it s mostly convention and maintaining compatibility with existing tools

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If you add a new line of text at the end of the existing file which does not already have a newline character at the end  the diff will show the old last line as having been modified  even though conceptually it wasn   t   This is at least one good reason to add a newline character at the end   Example  A file contains   A            do something     Hexdump   00000000  4128 2920 7b0a 2020 2020 2f2f 2064 6f20  A            do  00000010  736f 6d65 7468 696e 670a 7d              something     You now edit it to  A            do something      Useful comment   Hexdump   00000000  4128 2920 7b0a 2020 2020 2f2f 2064 6f20  A            do  00000010  736f 6d65 7468 696e 670a 7d0a 2f2f 2055  something      U 00000020  7365 6675 6c20 636f 6d6d 656e 742e 0a    seful comment     The git diff will show   -    No newline at end of file        Useful comment    In other words  it shows a larger diff than conceptually occurred  It shows that you deleted the line   and added the line   n  This is  in fact  what happened  but it   s not what conceptually happened  so it can be confusing

User · Answer

The core problem is what you define line and whether end-on-line character sequence is part of the line or not  UNIX-based editors  such as VIM  or tools  such as Git  use EOL character sequence as line terminator  therefore it s a part of the line  It s similar to use of semicolon     in C and Pascal  In C semicolon terminates statements  in Pascal it separates them

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For what it s worth  I encountered this when I created an IntelliJ project on a Mac  and then moved the project over to my Windows machine   I had to manually open every file and change the encoding setting at the bottom right of the IntelliJ window   Probably not happening to most if any who read this question but that could have saved me a couple of hours of work

User · Answer

Your original file probably had no newline character   However  some editors like gedit in linux silently adds newline at end of file  You cannot get rid of this message while using this kind of editors   What I tried to overcome this issue is to open file with visual studio code editor  This editor clearly shows the last line and you can delete the line as you wish

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It just indicates that the end of the file doesn t have a newline  It s not a catastrophe it s just a message to make it clearer that there isn t one when looking at a diff in the command line

[git] No newline at end of file

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