I have a hex file, I need to extract a range of it to a text file
From range:
To Range:
I need Output: AC:E4:B5:9A:53:1C
i tried many but it not really correct requirements, Output: Binary file filehex matches
grep "["'\x9f\x87\x6f\x11'"-"'\x9f\x87\x70\x11'"]" filehex > test.txt
hope someone can help me
Use -a to force the text interpretation of the input.
Use -o to only output the matching part.
The expression you used doesn't make much sense. It matches any characters in the set \x9, \x87, \x6f, and then the range \x11-\x9f, etc.
You are rather interested in something that starts with \x9\x87\x6f\x11 and ends in \x9f\x87\x70\x11, and there can be anything in between.
You can use cut to remove the leading and trailing 4 bytes.
grep -oa $'\x9f\x87\x6f\x11.*\x9f\x87\x70\x11' hexfile | cut -b5-21
If you know the length of the string will always be 17 bytes, you can use .\{17\} instead of .*.
Ok I've build randomly one binary $file
with your string at a location making hd command to split them.
Note: regarding k314159' comment, I use hd to produce hexdump output similarto CentOS's hexdump tool.
One shoot using sed:
hd $file |sed -e 'N;/ 9f \+\(|.*\n[0-9a-f]\+ \+\|\)87 \+\(|.*\n[0-9a-f]\+ \+\|\)6f \+\(|.*\n[0-9a-f]\+ \+\|\)11 /p;D;'
000161c0 96 7a b2 21 28 f1 b3 32 63 43 93 ff 50 a6 9f 87 |.z.!(..2cC..P...|
000161d0 6f 11 0d 7a a5 a9 81 9e 32 9d fb 71 27 6d 60 f2 |o..z....2..q'm`.|
0002c3a0
Explanation:
N merge next line in current buffer
\(|.*\n[0-9a-f]\+ \+\|\) match a | followed by anything and a newline (\n), then immediately an hexadecimal number and a space OR nothing.
p print current buffer (two lines)
D Delete upto newline in current buffer, keep last line for next sed loop.
The last hexadecimal 00028d2a correspond to the size of my binary $file:
printf "%x\n" $(stat -c %s $file)
Using bash + grep:
printf -v var "\x9f\x87\x6f\x11"
IFS=: read -r offset _ < <(grep -abo "$var" $file)
hd $file | sed -ne "$((offset/16-1)),+4p"
000161a0 b7 8f 4a 4d ed 89 6c 0b 25 f9 e7 c9 8c 99 6e 23 |..JM..l.%.....n#|
000161b0 3c ba 80 ec 2e 32 dd f3 a4 a2 09 bd 74 bf 66 11 |<....2......t.f.|
000161c0 96 7a b2 21 28 f1 b3 32 63 43 93 ff 50 a6 9f 87 |.z.!(..2cC..P...|
000161d0 6f 11 0d 7a a5 a9 81 9e 32 9d fb 71 27 6d 60 f2 |o..z....2..q'm`.|
000161e0 15 86 c2 bd 11 d0 08 90 c4 84 b9 80 04 4e 17 f1 |.............N..|
Where you could read your string:
000161c0 9f 87 | ..|
000161d0 6f 11 |o. |
For testing, I've built my test file by:
dd if=/vmlinuz bs=90574 count=1 of=/tmp/testfile
printf '\x9f\x87\x6f\x11' >>/tmp/testfile
dd if=/vmlinuz bs=90574 count=1 >>/tmp/testfile
file=/tmp/testfile
Use grep to search for the original binary file, not the hex dump. Extending choroba's answer, I think you may have problems with grep trying to interpret your search pattern as UTF-8 or some other encoding. You should temporarily set the environment variable LC_ALL=C for grep to treat each byte individually. Also, you can use the -P option to enable use of lookbehind and lookahead in your pattern. So your command becomes:
LANG=C grep -oaP $'(?<=\x9f\x87\x6f\x11).*(?=\x9f\x87\x70\x11)' binary-file > test.txt
Proof that it works:
$ echo $'BEFORE\x9f\x87\x6f\x11AC:E4:B5:9A:53:1C\x9f\x87\x70\x11AFTER' | LANG=C grep -oaP $'(?<=\x9f\x87\x6f\x11).*(?=\x9f\x87\x70\x11)'
AC:E4:B5:9A:53:1C
$
Related
I want to decode a base64 encoded string to human readable data, and seeking right encoding for the same.
This is the command that i am trying
echo H4sICJVHi14AA2ZsYWcyLnR4dAAzsvLzdHb193O1Kkktyk3KzLNKLjMp4gIAtRX2oBcAAAA= | base64 -d
Abve outputs to some fuzzy non human readable data.
�G�^flag2.txt3���tv��s�*I-�M�̳J.3)����
Why many characters are missed?
How can i read all the characters?
My gnome terminal is set to utf-8. Is there a better / wider encoding ? How do i set that?
Your Base64 encoded data is binary with mixed printable characters and mixed non-printable.
Lets see what it actually contain with hexdump:
<<<'H4sICJVHi14AA2ZsYWcyLnR4dAAzsvLzdHb193O1Kkktyk3KzLNKLjMp4gIAtRX2oBcAAAA=' base64 -d | hexdump -C
00000000 1f 8b 08 08 95 47 8b 5e 00 03 66 6c 61 67 32 2e |.....G.^..flag2.|
00000010 74 78 74 00 33 b2 f2 f3 74 76 f5 f7 73 b5 2a 49 |txt.3...tv..s.*I|
00000020 2d ca 4d ca cc b3 4a 2e 33 29 e2 02 00 b5 15 f6 |-.M...J.3)......|
00000030 a0 17 00 00 00 |.....|
00000035
You can extract valid text with the strings command:
<<<'H4sICJVHi14AA2ZsYWcyLnR4dAAzsvLzdHb193O1Kkktyk3KzLNKLjMp4gIAtRX2oBcAAAA=' base64 -d | strings
flag2.txt
J.3)
Or save it to a bin file:
<<<'H4sICJVHi14AA2ZsYWcyLnR4dAAzsvLzdHb193O1Kkktyk3KzLNKLjMp4gIAtRX2oBcAAAA=' >file.bin base64 -d
Lets check what it is:
file file.bin
file.bin: gzip compressed data, was "flag2.txt", last modified: Mon Apr 6 15:15:33 2020, from Unix, original size modulo 2^32 23
Since it is a gzip'ed data, lets gunzip it:
<file.bin gunzip
2:NICEONE:termbin:cv4r
Or doing it all in one-line:
<<<'H4sICJVHi14AA2ZsYWcyLnR4dAAzsvLzdHb193O1Kkktyk3KzLNKLjMp4gIAtRX2oBcAAAA=' base64 -d | gunzip
2:NICEONE:termbin:cv4r
I have a temperature sensor connected to a *nix system and the typical output is something like:
pi#raspberrypi $ cat /sys/bus/w1/devices/28-00000202070c/w1_slave
c3 00 4b 46 7f ff 0d 10 12 : crc=12 YES
c3 00 4b 46 7f ff 0d 10 12 t=12187
The result comes without any comma, but is assumed that is always coming with 3 digits after the comma, so in this example would be 12.187º.
I have implemented a filter that places a comma after the second char, and it works most of the time:
grep t= | awk '{print $10;}'| sed 's/t\=//g' | sed 's/\([0-9][0-9]\)\([0-9]\)/\1,\2/g'
However, during winter, temperature drops below 10º and my filter returns values like 95,32º (when it should be 9,532º).
Is there any way of counting characters from the right, so I could always count with the 3 digital characters (and avoiding this problem in temperatures below 10º)?
Thanks,
Joaoabs
awk can handle floating point operations:
awk '/t=/ { sub(/t=/,"",$NF); print $NF/1000}' /sys/bus/w1/devices/28-00000202070c/w1_slave
If I understand you correctly, then what you want to do is :
sed 's/\([0-9][0-9][0-9]\)$/,\1/g'
$ in a regex means 'the end' so this searches for 3 digits right at the end of a string and replaces them with comma+the found digits.
(Note: This should be the last part of your pipe, with the beginning unchanged.)
Using awk
awk -F= '/t=/ {print $NF/1000}' /sys/bus/w1/devices/28-00000202070c/w1_slave
12.187
Or store it to a variable:
temp=$(awk -F= '/t=/ {print $NF/1000}' /sys/bus/w1/devices/28-00000202070c/w1_slave)
echo "$temp"
12.187
don't do grep|awk|sed|sed..., try this:
...|awk -F't=' -v OFS='t=' 'NF>1{$2=sprintf("%'\''d",$2)}7'
test with your data:
kent$ echo "c3 00 4b 46 7f ff 0d 10 12 : crc=12 YES
c3 00 4b 46 7f ff 0d 10 12 t=12187"|awk -F't=' -v OFS='t=' 'NF>1{$2=sprintf("%'\''d",$2)}7'
c3 00 4b 46 7f ff 0d 10 12 : crc=12 YES
c3 00 4b 46 7f ff 0d 10 12 t=12,187
awk has the format pattern in 'printf' for your requirement. just use it.
if you just want to have the t= value:
awk -F't=' -v OFS='t=' 'NF>1{printf "%'\''d\n",$2}'
with same input:
kent$ echo "c3 00 4b 46 7f ff 0d 10 12 : crc=12 YES
c3 00 4b 46 7f ff 0d 10 12 t=12187"|awk -F't=' -v OFS='t=' 'NF>1{printf "%'\''d\n",$2}'
12,187
This is the script I've constructed
It takes a list of files according to the extension supplied as an argument.
It then removes everything before the pattern 00000000: in those files.
The pattern 00000000: is preceded by the string <pre>, it then removes those five first characters.
The script then removes the last three lines of the file
The script the outputs only the hexdump data of the file.
The script runs xxd to convert the hexdump to a file.jpg
if [[ $# -eq 0 ]] ; then
echo 'Run script as ./hexconv ext'
exit 0
fi
for file in *.$1
do
filename=$(basename $file)
extension="${filename##*.}"
filename="${filename%.*}"
sed -n '/00000000:/,$p' $file | sed '1s/^.....//' | head -n -3 | awk '{print $2" "$3" "$4" "$5" "$6" "$7" "$8" "$9" "$10" "$11" "$12" "$13" "$14" "$15" "$16" "$17}' | xxd -p -r > $filename.jpg
done
It works as I want it too, but I suspect there are things to improve it by, but alas, I am a novice in the use of awk and sed.
Excerpt from file
<th>response-head:</th>
<td>HTTP/1.1 200 OK
Date: Sun, 15 Dec 2013 04:27:04 GMT
Server: PWS/8.0.18
X-Px: ms h0-s34.p6-lhr ( h0-s35.p6-lhr), ht-d h0-s35.p6-lhr.cdngp.net
Etag: "4556354-9fbf8-4e40387aadfc0"
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0, max-age=0
Accept-Ranges: bytes
Content-Length: 654328
Content-Type: image/jpeg
Last-Modified: Thu, 15 Aug 2013 21:55:19 GMT
Pragma: no-cache
</td>
</tr>
</table>
<hr/>
<pre>00000000: ff d8 ff e0 00 10 4a 46 49 46 00 01 01 01 00 48 ......JFIF.....H
00000010: 00 48 00 00 ff e1 00 18 45 78 69 66 00 00 49 49 .H......Exif..II
00000020: 2a 00 08 00 00 00 00 00 00 00 00 00 00 00 ff ed *...............
00000030: 00 48 50 68 74 73 68 70 20 33 2e 30 00 .HPhotoshop 3.0.
00000040: 38 42 49 4d 04 04 00 00 00 00 00 1c 01 5a 00 8BIM..........Z.
00000050: 03 1b 25 47 1c 02 00 00 02 00 02 00 38 42 49 4d ..%G........8BIM
00000060: 04 25 00 00 00 00 00 10 fc e1 89 c8 b7 c9 78 .%.............x
00000070: 34 62 34 07 58 77 eb ff e1 03 a5 68 74 74 70 /4b4.Xw.....http
00000080: 3a 6e 73 2e 61 64 62 65 2e 63 6d ://ns.adobe.com/
00000090: 78 61 70 31 2e 30 00 3c 78 70 61 63 6b xap/1.0/.<?xpack
000000a0: 65 74 20 62 65 67 69 6e 3d 22 ef bb bf 22 20 69 et begin="..." i
000000b0: 64 3d 22 57 35 4d 30 4d 70 43 65 68 69 48 7a 72 d="W5M0MpCehiHzr
000000c0: 65 53 7a 4e 54 63 7a 6b 63 39 64 22 3e 20 3c eSzNTczkc9d"?> <
000000d0: 78 3a 78 6d 70 6d 65 74 61 20 78 6d 6c 6e 73 3a x:xmpmeta xmlns:
000000e0: 78 3d 22 61 64 62 65 3a 6e 73 3a 6d 65 74 61 x="adobe:ns:meta
000000f0: 22 20 78 3a 78 6d 70 74 6b 3d 22 41 64 62 /" x:xmptk="Adob
00000100: 65 20 58 4d 50 20 43 72 65 20 35 2e 30 2d 63 e XMP Core 5.0-c
00000110: 30 36 31 20 36 34 2e 31 34 30 39 34 39 2c 20 32 061 64.140949, 2
00000120: 30 31 30 31 32 30 37 2d 31 30 3a 35 37 3a 010/12/07-10:57:
Although #CodeGnome is right and this might belong to Code Review SE, here you go anyway:
Slightly more efficient to combine the multiple sed commands into one, for example:
sed -n -e 's/^<pre>//' -e '/00000000:/,$p'
I decided to retract this part, as I'm not all that sure it's any better or clearer. Your version is fine, except that s/^<pre>// is better than s/^.....//.
Use exit 1 when checking the number of arguments to signal an error
What is for file in *. there? Iterate for all files ending with a dot? Typo?
Unless you're 100% sure the filenames will never contain spaces, you should quote them, but don't quote where you don't need, for example:
filename=$(basename "$file") # need to quote
extension=${filename##*.} # no need,
filename=${filename%.*} # no need
sed ... "$file" # need to quote
... | xxd > "$filename".jpg # need to quote
The last awk could be shorter and less error prone as a loop:
... | awk '{printf $2; for (i=3; i<=17; ++i) printf " " $i; print ""}'
It seems you want to learn. You might be interested in this other answer too: What are the rules to write robust shell scripts?
The error message should be sent to stderr, should not hard-code the name of the script in case you rename it later, and should exit with a nonzero value.
if (( ! $# )); then
echo >&2 "Run script as '$0' \$extension"
exit 1
fi
If you're going to put the then on the same line as the if, then you should put the do on the same line as the for, too, for consistency:
for file in *.$1; do
Using file for the full name and filename for the basename is confusing variable name choice. I would use basename for the variable, to match the operation. And you need to quote the parameter expansion:
basename=$(basename "$file")
But you don't need to quote the right hand side of an assignment:
extension=${basename##*.}
The part of a filename without the extension is sometimes called the root (in vi and csh :-modifiers, you get it with :r)... using that name would be less confusing than changing an existing variable and reusing it:
root=${basename%.*}
As far as the actual pipeline, I would reorder it to put the head before the awk, since the sed and the head are all about what lines to print out and should be grouped together before the awk which modifies those selected lines. I would also use a loop and printf to make the awk a little more wieldy:
sed -n '/0\{8\}:/,$p' "$file" |
head -n -3 |
awk '{ printf "%s", $2; for (f=3;f<=17;++f) { printf " %s", $f }; print "" }' |
xxd -p -r > "$root.jpg"
done
I have file Blackberry jad file:
RIM-COD-URL-12: HelloWorld-12.cod
RIM-COD-Size: 68020
RIM-MIDlet-Icon-2-1: ____HOVER_ICON_res/icon/blackberry/icon-68.png,focused
RIM-COD-URL-11: HelloWorld-11.cod
RIM-MIDlet-Icon-Count-2: 1
RIM-COD-URL-10: HelloWorld-10.cod
RIM-MIDlet-Icon-Count-1: 1
MIDlet-Vendor: Vasia Pupkin
RIM-MIDlet-Icon-1-1: res\icon\blackberry\____HOVER_ICON_icon-68.png,focused
Manifest-Version: 1.0
RIM-MIDlet-Flags-1: 0
RIM-COD-SHA1-38: 9a c8 b3 35 72 de 34 5e 7a 0a 5b 9e c3 3a 65 4c 20 0f 8e 50
I just want to get lines begin with RIM-COD-.
Can you provide me solutions for awk or sed?
Use sed -n and only print lines that match RIM-COD.
sed -n -e '/^RIM-COD-/p' yourfile.txt
Try doing this :
awk '/^RIM-COD/' file.txt
Or
grep "^RIM-COD" file.txt
Or
sed -n '/^RIM-COD/p' file.txt
The following is a bash file I wrote to convert all C++ style(//) comments in a C file to C style(/**/).
#!/bin/bash
lang=`echo $LANG`
# It's necessary to change the local setting. I don't know why.
export LANG=C
# Can comment the following statement if there is not dos2unix command.
dos2unix -q $1
sed -i -e 's;^\([[:blank:]]*\)//\(.*\);\1/* \2 */;' $1
export LANG=$lang
It works. But I found a problem I cannot explain. In default, my local setting is en_US.UTF-8. And in my C code, there are comments written in Chinese, such as
// some english 一些中文注释
If I don't change the local setting, i.e., do not run the statement export LANG=C, I'll get
/* some english */一些中文注释
instead of
/* some english 一些中文注释*/
I don't know why. I just find a solution by try and error.
After read Jonathan Leffler's answer, I think I've make some mistake leading to some misunderstand. In the question, those Chinese words were inputed in Google Chrome and were not the actual words in my C file. 一些中文注释 just means some Chinese comments.
Now I inputed // some english 一些中文注释 in Visual C++ 6.0 in Windows XP, and copied the c file to Debian. Then I just run sed -i -e 's;^([[:blank:]])//(.);\1/ \2 /;' $1 and got
/* some english 一些 */中文注释
I think it's different character coding(GB18030, GBK, UTF-8?) cause the different results.
The following is my results gotten on Debian
~/sandbox$ uname -a
Linux xyt-dev 2.6.30-1-686 #1 SMP Sat Aug 15 19:11:58 UTC 2009 i686 GNU/Linux
~/sandbox$ echo $LANG
en_US.UTF-8
~/sandbox$ cat tt.c | od -c -t x1
0000000 / / s o m e e n g l i s h
2f 2f 20 73 6f 6d 65 20 65 6e 67 6c 69 73 68 20
0000020 322 273 320 251 326 320 316 304 327 242 312 315
d2 bb d0 a9 d6 d0 ce c4 d7 a2 ca cd
0000034
~/sandbox$ ./convert_comment_style_cpp2c.sh tt.c
~/sandbox$ cat tt.c | od -c -t x1
0000000 / * s o m e e n g l i s h
2f 2a 20 20 73 6f 6d 65 20 65 6e 67 6c 69 73 68
0000020 322 273 320 251 * / 326 320 316 304 327 242 312 315
20 d2 bb d0 a9 20 2a 2f d6 d0 ce c4 d7 a2 ca cd
0000040
~/sandbox$
I think these Chinese Character encoding with 2 byte(Unicode).
There are another example:
~/sandbox$ cat tt.c | od -c -t x1
0000000 / / I n W i n d o w : 250 250 ?
2f 2f 20 49 6e 57 69 6e 64 6f 77 3a 20 a8 a8 3f
0000020 1 ?
31 3f
0000022
~/sandbox$ ./convert_comment_style_cpp2c.sh tt.c
~/sandbox$ cat tt.c | od -c -t x1
0000000 / * I n W i n d o w : *
2f 2a 20 20 49 6e 57 69 6e 64 6f 77 3a 20 20 2a
0000020 / 250 250 ? 1 ?
2f a8 a8 3f 31 3f
Which platform are you working on? Your sed script works fine on MacOS X without changing locale. The Linux terminal was less happy with the Chinese characters, but it is not setup to use UTF-8. Moreover, a hex dump of the string that it did get contained a zero byte 0x00 where the Chinese started, which might lead to the confusion. (I note that your regex adds a space before the comment text if it starts // with a space.)
MacOS X (10.6.8)
The 'odx' command use is a hex-dump program.
$ echo "// some english 一些中文注释" > x3.utf8
$ odx x3.utf8
0x0000: 2F 2F 20 73 6F 6D 65 20 65 6E 67 6C 69 73 68 20 // some english
0x0010: E4 B8 80 E4 BA 9B E4 B8 AD E6 96 87 E6 B3 A8 E9 ................
0x0020: 87 8A 0A ...
0x0023:
$ utf8-unicode x3.utf8
0x2F = U+002F
0x2F = U+002F
0x20 = U+0020
0x73 = U+0073
0x6F = U+006F
0x6D = U+006D
0x65 = U+0065
0x20 = U+0020
0x65 = U+0065
0x6E = U+006E
0x67 = U+0067
0x6C = U+006C
0x69 = U+0069
0x73 = U+0073
0x68 = U+0068
0x20 = U+0020
0xE4 0xB8 0x80 = U+4E00
0xE4 0xBA 0x9B = U+4E9B
0xE4 0xB8 0xAD = U+4E2D
0xE6 0x96 0x87 = U+6587
0xE6 0xB3 0xA8 = U+6CE8
0xE9 0x87 0x8A = U+91CA
0x0A = U+000A
$ sed 's;^\([[:blank:]]*\)//\(.*\);\1/* \2 */;' x3.utf8
/* some english 一些中文注释 */
$
All of which looks clean and tidy.
Linux (RHEL 5)
I copied the x3.utf8 file to a Linux box, and dumped it. Then I ran the sed script on it, and all seemed OK:
$ odx x3.utf8
0x0000: 2F 2F 20 73 6F 6D 65 20 65 6E 67 6C 69 73 68 20 // some english
0x0010: E4 B8 80 E4 BA 9B E4 B8 AD E6 96 87 E6 B3 A8 E9 ................
0x0020: 87 8A 0A ...
0x0023:
$ sed 's;^\([[:blank:]]*\)//\(.*\);\1/* \2 */;' x3.utf8 | odx
0x0000: 2F 2A 20 20 73 6F 6D 65 20 65 6E 67 6C 69 73 68 /* some english
0x0010: 20 E4 B8 80 E4 BA 9B E4 B8 AD E6 96 87 E6 B3 A8 ...............
0x0020: E9 87 8A 20 2A 2F 0A ... */.
0x0027:
$
So far, so good. I also tried:
$ echo $LANG
en_US.UTF-8
$ echo $LC_CTYPE
$ env | grep LC_
$ bash --version
GNU bash, version 3.2.25(1)-release (x86_64-redhat-linux-gnu)
Copyright (C) 2005 Free Software Foundation, Inc.
$ cat x3.utf8
// some english 一些中文注释
$ echo $(<x3.utf8)
// some english 一些中文注释
$ sed 's;^\([[:blank:]]*\)//\(.*\);\1/* \2 */;' x3.utf8
/* some english 一些中文注释 */
$
So, the terminal is nominally working in UTF-8 after all, and it certainly seems display the data OK.
However, if I echo the string at the terminal, it gets into a tizzy. When I cut'n'pasted the string to the Linux terminal, it said:
$ echo "// some english d8d^G:
> "
// some english d8d:
$
and beeped.
$ echo "// some english d8d^G:
> " | odx
0x0000: 2F 2F 20 73 6F 6D 65 20 65 6E 67 6C 69 73 68 20 // some english
0x0010: 64 38 64 07 3A 0A 0A d8d.:..
0x0017:
$
I'm not quite sure what to make of that. I think it means that something in the input side of bash is having some problems, but I'm not quite sure. I also am getting slightly inconsistent results. The first time I tried it, I got:
$ cat > xxx
's;^\([[:blank:]]*\)//\(.*\);\1/* \2 */;'
// some english d8^#d:^[d8-f^Gf3(i^G
$ odx xxx
0x0000: 27 73 3B 5E 5C 28 5B 5B 3A 62 6C 61 6E 6B 3A 5D 's;^\([[:blank:]
0x0010: 5D 2A 5C 29 2F 2F 5C 28 2E 2A 5C 29 3B 5C 31 2F ]*\)//\(.*\);\1/
0x0020: 2A 20 5C 32 20 2A 2F 3B 27 0A 2F 2F 20 73 6F 6D * \2 */;'.// som
0x0030: 65 20 65 6E 67 6C 69 73 68 20 64 38 00 64 3A 1B e english d8.d:.
0x0040: 64 38 2D 66 07 66 33 28 69 07 0A 0A d8-f.f3(i...
0x004C:
$
And in that hex dump, you can see a 0x00 byte (offset 0x003C). That appears at the position where you got the end comment, and a null there could confuse sed; but the whole input is such a mess it is hard to know what to make of it.
Okay, here's the correct answer...
The GNU regular expression library (regex) doesn't match everything when you put a . in your expression. Yup, I know how braindead that sounds.
The problem comes from the word "character", now reasonable people will say that everything that's in the input file for sed is characters. And even in your case they are perfectly correct. But regex has been programmed to required that the input be perfectly correctly formatted characters of the current locale character set (UTF-8) if they're correctly formatted characters for the Windows character set (UTF-16) they're not "characters".
So as . only matches "characters" it doesn't match your characters.
If you used the regex //.*$, ie: pinned it to the end of the line it wouldn't match at all because there's something that's not a "character" between the // and the end of the line.
And no you can't do anything like //\(.\|[^.]\)*$, it's just impossible to match those characters without switching to the C locale.
This will also, sometimes, destroy 8-bit transparency; ie: a binary piped through sed will get corrupted even if no changes are made.
Fortunately the C locale still uses the reasonable interpretation so anything that's not a perfectly correctly formatted ASCII-68 character is still a "character".