Using bash to reformat "#include" in a list of files using regex

Question

Consider the following code that does a simple loop over code files:

#!/bin/bash
dir="."
find $dir -name *.cpp -o -name *.h | while read file; do
    echo "processing: "$file
    # Process file here
done

Every file start with messy includes like this

#include<iostream>
#include <vector>
#include"this_is_file1.h"
#include "this_is_file2.h"
#include "This_Is_File3.h"
#include"thisIsFile4.h"
#include "ThisIsFile5.h"
#include"dir/thisIsFile6.h"
#include "dir/ThisIsFile7.h"
#include "dir/ThisIsFile8.txx"
#include "dir/ThisIsFILe9.txx"

that I would like to transform like this (and overwrite the old file)

#include <iostream>
#include <vector>
#include "this_is_file1.h"
#include "this_is_file2.h"
#include "this_is_file3.h"
#include "this_is_file4.h"
#include "this_is_file5.h"
#include "this_is_file6.h"
#include "this_is_file7.h"
#include "this_is_file8.txx"
#include "this_is_file9.txx"

More formally:

• There should be exactly one space between the include and the file name
• There should not be any capital letter, and every consecutive sequence of capital letters that has been replaced should be preceded by exactly one underscore, except if it's the beginning of the file name
• There should not be any directory name

How to do that with bash?

Answer 1

The following sed script should do it:

s/\(#include\) *\([^ ]\+\)/\1 \2/

/^#include "/ {
    s/".*\//"/
    s/"\(.\)/"\l\1/g
    s/\([^A-Z]\)\([A-Z]\)/\1_\l\2/g
    s/_\+/_/g
}

This can be applied in place to files by running:

sed -i.bak -f fix.sed input...

(This assumes that the script above is called fix.sed, and any number of files can be given as arguments afterwards. Remove .bak if you do not want any backups created.)

The first sed replacement expression matches #include followed by a possibly empty run of spaces (\ *), and replaces that run with a single space. It also turns the rest of the line ([^ ]\+) to lowercase (using \l).

The next four sed expressions, all of which only apply to lines that start with #include ", do the following:

1. Strip path name (everything up to and including the last slash);

2. turn the first character between quotes to lowercase;

3. at the start of each run of uppercase letters, insert underscore and turn first character of run to lowercase;

4. squeeze runs of underscore possibly inserted by previous steps.

This is imperfect, but does translate your sample input as intended.

Answer 2

You might find using a tool such as astyle formats your code neatly, and does more than just fixes up the #include lines.

Your code is fine, as-is, but if you don't have spaces in your filenames or other oddities you could just as well use find:

astyle --style=allman -A1 --indent=spaces=4  \
   --break-blocks --pad-oper --pad-header --unpad-paren \
   --max-code-length=200 \
   $(find . -name '*.cpp' -print) $(find . -name '*.h' -print)

Answer 3

perl -i.bak -pe '
   if( s!(#include) *(["<])(.*/)?!$1 $2!){  ## if is a include line
        s/(?<=[a-z])(?=[A-Z])/_/g;          ##   insert CamelCase "_"
        tr/A-Z/a-z/ }'   file               ##   lowercase ids