Magic
Dan Tobias (Talk | contribs) |
(Describe what is magic in programming/computing terms. Add references.) |
||
| (One intermediate revision by one user not shown) | |||
| Line 3: | Line 3: | ||
|subcat=Elements of File Formats | |subcat=Elements of File Formats | ||
}} | }} | ||
| − | I'm sure there are all sorts of almanacs with custom notation that [https://harrypotter.fandom.com/wiki/Magic talk about magic], but this page exists to talk about (and link to/from elsewhere on the wiki where needed) the convention of using the first few bytes of a file to notate/detect the reported format, "as is by magic" (actually by table lookups). | + | I'm sure there are all sorts of almanacs with custom notation that [https://harrypotter.fandom.com/wiki/Magic talk about magic], but this page exists to talk about (and link to/from elsewhere on the wiki where needed) the convention of (typically) using the first few bytes of a file to notate/detect the reported format, "as is by magic" (actually by table lookups). |
| + | |||
| + | [[wikipedia:Magic number (programming)|Magic]] is a string of unique hexadecimal pattern(s) to look for, used in [[File command|<code>file</code>]] as, "relatively quick-running heuristics to determine file type, it can report misleading information. The command can be fooled, for example, by including a magic number in the content even if the rest of the content does not match what the magic number indicates. The command report cannot be taken as completely trustworthy."<ref>[[wikipedia:File_(command)]]</ref> This method, however, is beneficial in somewhat quickly ascertaining whether a or an (extension-less) file is human-readable, or machine code, as opposed to using utilities such as <code>cat</code> to show the contents of a binary file to terminal, can ruin it due to the use of [[wikipedia:Control character|control characters]].<ref>[https://unix.stackexchange.com/a/119485 Why (and how) did using cat on binary files mess up the terminal? - Unix & Linux Stack Exchange]</ref> | ||
| + | |||
| + | It is also used as a [[wikipedia:Library (computing)|library]] containing a database of [[wikipedia:Magic number (programming)|magic numbers]] that can be used, for instance [https://github.com/ReFirmLabs/binwalk binwalk] to, "identify, and optionally extract, files and data that have been embedded inside of other files"<ref>[https://github.com/ReFirmLabs/binwalk?tab=readme-ov-file#what-does-it-do What does it do? - binwalk - GitHub]</ref>, based on libmagic signatures. | ||
| + | |||
| + | == References == | ||
| + | <references/> | ||
| + | |||
| + | [[Category:File Format Identification]] | ||
Latest revision as of 12:56, 15 August 2025
I'm sure there are all sorts of almanacs with custom notation that talk about magic, but this page exists to talk about (and link to/from elsewhere on the wiki where needed) the convention of (typically) using the first few bytes of a file to notate/detect the reported format, "as is by magic" (actually by table lookups).
Magic is a string of unique hexadecimal pattern(s) to look for, used in file as, "relatively quick-running heuristics to determine file type, it can report misleading information. The command can be fooled, for example, by including a magic number in the content even if the rest of the content does not match what the magic number indicates. The command report cannot be taken as completely trustworthy."[1] This method, however, is beneficial in somewhat quickly ascertaining whether a or an (extension-less) file is human-readable, or machine code, as opposed to using utilities such as cat to show the contents of a binary file to terminal, can ruin it due to the use of control characters.[2]
It is also used as a library containing a database of magic numbers that can be used, for instance binwalk to, "identify, and optionally extract, files and data that have been embedded inside of other files"[3], based on libmagic signatures.
