Perl regular expression substitution changes only first letter of each line

Question

I am having trouble doing the simplest of Perl REGEX. It is working correctly in Notepad++ but not Perl.

open FILE, "Something.txt";
while (<FILE>) {
   s/./f/;
    print;
}

However the output only changes the first letter of each line to F. When this regular expression is clearly saying change every character to F!

Answer 1

我已经有一段时间没有使用过perl了，但是尝试s/./f/g （根据Quentin的评论（感谢），g使它成为全局的，而不是在第一次比赛之后停止）。

Answer 2

您需要添加g修饰符以使其成为全局变量，否则它将在第一个匹配项后停止。

s/./f/g

Answer 3

See the following sample code :

The fle :

$ cat /tmp/test
aaaa
bbbb
cccc

The Perl code (I use perlconsole )

Perl> open FH, "<", "/tmp/test"
1

Perl> while (<FH>) { s/./f/g; print; }
ffff
ffff
ffff


Perl> close FH
1

Perl> 

The g modifier in the substitution means all occurrences, see http://perldoc.perl.org/perlre.html#Modifiers

Answer 4

You need to flag it for global change:

open FILE, "Something.txt";
while (<FILE>) {
   s/./f/g;
    print;
}
CLOSE (FILE);