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The -i means the output of the program is saved into the input file.
The -n means to execute the program for each line of the input file(s).
The -e means that the following string (enclosed in single quotes) is the program. Here it is with some formatting to help you read it:
Code:
if (!/^--/) {
s/,1/ - on/;
s/,0/ - off/;
print;
}
The clause of the if says, "only do this for line which don't begin with "--".
Inside the if block are two replacements, which substitute ",1" for " - on", and ",0" for " - off". The line is then printed.
Note that none of these operations say what they are working on. This is a feature of Perl that many operations have a default argument, which is usually the $_ variable. This means "the current input line" as set by the <FILEHANDLE> operator, or in the case of your using the -n option, each line of the input file(s).
Last edited by matthewg42; 05-13-2008 at 11:15 AM.
Reason: typo
The -i means the output of the program is saved into the input file.
The -n means to execute the program for each line of the input file(s).
The -e means that the following string (enclosed in single quotes) is the program. Here it is with some formatting to help you read it:
Code:
if (!/^--/) {
s/,1/ - on/;
s/,0/ - off/;
print;
}
The clause of the if says, "only do this for line which don't begin with "--".
Inside the if block are two replacements, which substitute ",1" for " - on", and ",0" for " - off". The line is then printed.
Note that none of these operations say what they are working on. This is a feature of Perl that many operations have a default argument, which is usually the $_ variable. This means "the current input line" as set by the <FILEHANDLE> operator, or in the case of your using the -n option, each line of the input file(s).
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