I want to find and delete all even bytes from a file given in command line. Is there any command for this situation?
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Answer
I think this does what you want. It dumps the file as continuous plain hex, then reads two bytes, saving them for later and then two more bytes. Then it outputs the bytes it saved and pipes the whole lot back into xxd to “reconstruct”:
xxd -p INPUT | sed -E 's/(..)../1/g' | xxd -r -p > OUTPUT
So, if I dump a PNG image like this:
xxd image.png 00000000: 8950 4e47 0d0a 1a0a 0000 000d 4948 4452 .PNG........IHDR 00000010: 0000 0064 0000 0064 0203 0000 000d 8c7d ...d...d.......} 00000020: c700 0000 0467 414d 4100 00b1 8f0b fc61 .....gAMA......a 00000030: 0500 0000 2063 4852 4d00 007a 2600 0080 .... cHRM..z&... 00000040: 8400 00fa 0000 0080 e800 0075 3000 00ea ...........u0... 00000050: 6000 003a 9800 0017 709c ba51 3c00 0000 `..:....p..Q<... 00000060: 0950 4c54 4500 0000 ff00 00ff ffff 6719 .PLTE.........g. 00000070: 641e 0000 0001 624b 4744 0266 0b7c 6400 d.....bKGD.f.|d. 00000080: 0000 0774 494d 4507 e404 1c0a 0820 506e ...tIME...... Pn 00000090: 92c5 0000 0025 4944 4154 48c7 6360 1805 .....%IDATH.c`.. 000000a0: a300 0c58 4361 2064 5466 5466 5466 5466 ...XCa dTfTfTfTf 000000b0: 5466 5406 8fcc 2818 3100 00e8 0fcb 7f57 TfT...(.1......W 000000c0: afef dd00 0000 2574 4558 7464 6174 653a ......%tEXtdate: 000000d0: 6372 6561 7465 0032 3032 302d 3034 2d32 create.2020-04-2 000000e0: 3854 3130 3a30 383a 3332 2b30 303a 3030 8T10:08:32+00:00 000000f0: d513 d3d0 0000 0025 7445 5874 6461 7465 .......%tEXtdate 00000100: 3a6d 6f64 6966 7900 3230 3230 2d30 342d :modify.2020-04- 00000110: 3238 5431 303a 3038 3a33 322b 3030 3a30 28T10:08:32+00:0 00000120: 30a4 4e6b 6c00 0000 0049 454e 44ae 4260 0.Nkl....IEND.B` 00000130: 82
and then put that through my filter and display it again:
xxd -p image.png | sed -E 's/(..)../1/g' | xxd -r -pp | xxd 00000000: 894e 0d1a 0000 4944 0000 0000 0200 008c .N....ID........ 00000010: c700 0441 4100 8ffc 0500 2048 4d00 2600 ...AA..... HM.&. 00000020: 8400 0000 e800 3000 6000 9800 70ba 3c00 ......0.`...p.<. 00000030: 094c 4500 ff00 ff67 6400 0062 4702 0b64 .LE....gd..bG..d 00000040: 0007 4945 e41c 0850 9200 0049 4148 6318 ..IE...P...IAHc. 00000050: a30c 4320 5454 5454 5454 8f28 3100 0f7f ..C TTTTTT.(1... 00000060: afdd 0025 4574 6165 6365 7400 3030 302d ...%Etaecet.000- 00000070: 3831 3a38 332b 3030 d5d3 0000 7458 6474 81:83+00....tXdt 00000080: 3a6f 6979 3232 2d34 3254 3030 3a32 303a :oiy22-42T00:20: 00000090: 304e 6c00 0045 4442 82 0Nl..EDB.