macOS sed - 复杂的替换命令

Question

I have a text file with a lot of lines and need to do some complex substitutions using macOS sed. It's a bit hard to explain my problem so I'll show you an example first:

The file:

#00101:A9AA%AAB
#03901:%E+2100009+X3800
#06008:01020304

Expected output:

#00101:0000%A00
#03901:%E+2000000+X0000
#06008:01020304

For all lines starting with "#xxx01:" (where x represents any digit), I need to replace all alphanumeric characters (AZ, 0-9) with "0", except the numbers before the ":", and any two-character sequences starting with "%" or "+".

I am aware of the basic substitution and exception commands, as well as using "^" to search for a pattern at the start of a line, but I am confused as to how to combine all those commands. How should I go about doing this? Non-sed solutions are welcome if this is impossible in sed.

Answer 1

Create a file script.sed containing:

/^#[0-9]{3}01:/ {
    :r
    s/:((0|[+%]..)*)[A-Za-z1-9]/:\10/
    t r
}

Call the file containing your sample input data data . Run the command shown to get the required output:

$ sed -E -f script.sed data
#00101:0000%AA0
#03901:%E+0000000+X3000
#06008:01020304
$

The option -E tells sed to use extended regular expressions. The option -f tells it to read the program from the file script.sed .

The pattern /^#[0-9]{3}01:/ looks for lines starting with a # , followed by 3 digits, 01 and a colon. The lines between { and } are executed for each matching line.

The line :r creates a label r that can be branched to with the b or t commands. The t r branches to label r if there has been a successful s/// command since the last t command.

The s/:((0|[+%]..)*)[A-Za-z1-9]/:\10/ command searches for the colon followed by any sequence of 0 s or +.. or %.. characters (where the dots match any character) and then followed by an alphanumeric character other than 0 . It replaces that with the colon, the remembered matches, and a 0 to replace the other alphanumeric character. If you don't omit the 0 , you end up with an infinite loop.

You can also use a command-line script instead of a script file, possibly with several -e options (one per line of the script file) or with a single script option and enough semicolons.