From 15230bbb9b1f69def9b0e1b41a097638c0fda734 Mon Sep 17 00:00:00 2001 From: johannst Date: Tue, 28 Apr 2020 09:11:18 +0000 Subject: deploy: fef4d6ff2ad9f48e6dccde0f061453e6a3ac624e --- od.html | 260 ---------------------------------------------------------------- 1 file changed, 260 deletions(-) delete mode 100644 od.html (limited to 'od.html') diff --git a/od.html b/od.html deleted file mode 100644 index 7b838b1..0000000 --- a/od.html +++ /dev/null @@ -1,260 +0,0 @@ - - - - - - od - Notes - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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od(1)

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  od [opts] <file>
-    -An         don't print addr info
-    -tx4        print hex in 4 byte chunks
-    -ta         print as named character
-    -tc         printable chars or backslash escape
-    -w4         print 4 bytes per line
-    -j <n>      skip <n> bytes from <file> (hex if start with 0x)
-    -N <n>      dump <n> bytes (hex of start with 0x)
-
-

ASCII to hex string

-
  echo -n AAAABBBB | od -An -w4 -tx4
-    >> 41414141
-    >> 42424242
-
-  echo -n '\x7fELF\n' | od -tx1 -ta -tc
-    >> 0000000  7f  45  4c  46  0a      # tx1
-    >>         del   E   L   F  nl      # ta
-    >>         177   E   L   F  \n      # tc
-
-

Extract parts of file

-

For example .rodata section from an elf file. We can use readelf to get the -offset into the file where the .rodata section starts.

-
  readelf -W -S foo
-    >> Section Headers:
-    >> [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
-    >> ...
-    >> [15] .rodata           PROGBITS        00000000004009c0 0009c0 000030 00   A  0   0 16
-
-

With the offset of -j 0x0009c0 we can dump -N 0x30 bytes from the beginning of -the .rodata section as follows:

-
  od -j 0x0009c0 -N 0x30 -tx4 -w4 foo
-    >> 0004700 00020001
-    >> 0004704 00000000
-    >> *
-    >> 0004740 00000001
-    >> 0004744 00000002
-    >> 0004750 00000003
-    >> 0004754 00000004
-
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Note: Numbers starting with 0x will be interpreted as hex by od.

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