[SOLVED] How to add newline character at the end of many files

Issue

I've a lot of PHP files and I'd like to fix newline character after the last line (if not present) with a bash script.

Is there any command to to that easily?

Thanks :)

Solution

Short and quick tee

But adding a newline at end of each files. For strictly adding a newline at end of files where there are not, please go to second part of this answer!

tee is the tool you're searching for:

Simply:

tee -a <<<'' file1 file2 ...

or

find /path -type f ! -empty -name '*.php' -exec tee -a <<<'' {} +

Warning: Don't miss -a option!

It's very quick, but add a newline on each files.

(You could whipe in a second command like sed '${/^$/d}' -i file1 file2 ... all empty last lines in all files. ;)

(Warning again: I insist: if you miss -a flag for tee command, this will shortly and quickly replace the content of each file found by a newline!! So all your files will become empty!)

Some explanation:

from man tee:

NAME
       tee - read from standard input and write to standard output and files

SYNOPSIS
       tee [OPTION]... [FILE]...

DESCRIPTION
       Copy standard input to each FILE, and also to standard output.

       -a, --append
              append to the given FILEs, do not overwrite

• So tee will reproduce, appending (because of option a), to each file submited as argument, what become on standard input.
• bash feature: "here strings" (see man -Pless\ +/Here.Strings bash), you could use command <<<"here string"" in replacement of echo "here string"| command. For this, bash add a newline to submited string (even empty string: <<<'').

Slower, but stronger

fix newline character after the last line (if not present)

Stay very quick because of limited forks, but one fork to tail -c1 have to be done for each files anyway!

while IFS= read -d '' -r file
do
    IFS= read -d "" chr < <(
        exec tail -c1 "$file"
    )
    if [[ $chr != $'\n' ]]
    then
        echo >> "$file"
    fi   
done < <(
    find . -type f ! -empty -name '*.php' -print0
)

Could by written more compact:

while IFS= read -d '' -r file; do
    IFS= read -d "" chr < <( exec tail -c1 "$file" )
    [[ $chr != $'\n' ]] && echo >> "$file"
done < <( find . -type f ! -empty -name '*.php' -print0 )

• find -print0 print each filename separated by a null character \0.
• IFS= read -d '' -r file don't consider special characters nor spaces, so $file could hold any kind of filename, event containing spaces or accented characters.
• exec tell bash to execute tail as subprocess, avoid default second fork running tail in a subsubprocess.
• tail -c1 read last caracter of $file
• IFS= read -d "" chr store last caracter into $chr variable.

Answered By - F. Hauri - Give Up GitHub

Answer Checked By - Cary Denson (WPSolving Admin)