The radare2 search engine is based on work done by esteve, plus multiple features implemented on top of it. It supports multiple keyword searches, binary masks, and hexadecimal values. It automatically creates flags for search hit locations ease future referencing.
Search is initiated by / command.
[0x00000000]> /?
|Usage: /[!bf] [arg]Search stuff (see 'e??search' for options)
|Use io.va for searching in non virtual addressing spaces
| / foo\x00 search for string 'foo\0'
| /j foo\x00 search for string 'foo\0' (json output)
| /! ff search for first occurrence not matching, command modifier
| /!x 00 inverse hexa search (find first byte != 0x00)
| /+ /bin/sh construct the string with chunks
| // repeat last search
| /a jmp eax assemble opcode and search its bytes
| /A jmp find analyzed instructions of this type (/A? for help)
| /b search backwards, command modifier, followed by other command
| /B search recognized RBin headers
| /c jmp [esp] search for asm code matching the given string
| /ce rsp,rbp search for esil expressions matching
| /C[ar] search for crypto materials
| /d 101112 search for a deltified sequence of bytes
| /e /E.F/i match regular expression
| /E esil-expr offset matching given esil expressions %%= here
| /f search forwards, command modifier, followed by other command
| /F file [off] [sz] search contents of file with offset and size
| /g[g] [from] find all graph paths A to B (/gg follow jumps, see search.count and
anal.depth)
| /h[t] [hash] [len] find block matching this hash. See ph
| /i foo search for string 'foo' ignoring case
| /m magicfile search for matching magic file (use blocksize)
| /M search for known filesystems and mount them automatically
| /o [n] show offset of n instructions backward
| /O [n] same as /o, but with a different fallback if anal cannot be used
| /p patternsize search for pattern of given size
| /P patternsize search similar blocks
| /r[erwx][?] sym.printf analyze opcode reference an offset (/re for esil)
| /R [grepopcode] search for matching ROP gadgets, semicolon-separated
| /s search for all syscalls in a region (EXPERIMENTAL)
| /v[1248] value look for an `cfg.bigendian` 32bit value
| /V[1248] min max look for an `cfg.bigendian` 32bit value in range
| /w foo search for wide string 'f\0o\0o\0'
| /wi foo search for wide string ignoring case 'f\0o\0o\0'
| /x ff..33 search for hex string ignoring some nibbles
| /x ff0033 search for hex string
| /x ff43:ffd0 search for hexpair with mask
| /z min max search for strings of given size
Because everything is treated as a file in radare2, it does not matter whether you search in a socket, a remote device, in process memory, or a file.