OpenBSD-4.6/usr.bin/strings/strings.1

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.\"     @(#)strings.1	8.1 (Berkeley) 6/6/93
.\"
.Dd $Mdocdate: February 8 2009 $
.Dt STRINGS 1
.Os
.Sh NAME
.Nm strings
.Nd find printable strings in a file
.Sh SYNOPSIS
.Nm strings
.Op Fl afo
.Op Fl m Ar number
.Op Fl n Ar number
.Op Fl t Ar radix
.Op Ar file ...
.Sh DESCRIPTION
.Nm
displays the sequences of printable characters in each of the specified
files, or in the standard input, by default.
By default, a sequence must be at least four characters in length
before being displayed.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl a
By default,
.Nm
only searches the text and data segments of object files.
The
.Fl a
option causes
.Nm
to search the entire object file.
.It Fl f
Each string is preceded by the name of the file
in which it was found.
.It Fl m Ar number
Specifies the maximum number of characters in a sequence to be
.Ar number ,
instead of unlimited.
.It Fl n Ar number
Specifies the minimum number of characters in a sequence to be
.Ar number ,
instead of four.
.It Fl o
Each string is preceded by its octal offset in the file.
.It Fl t Ar radix
Each string is preceded by its offset in the file.
The first character of
.Ar radix
determines the radix of the offset:
.Sq o
for octal;
.Sq d
for decimal; or
.Sq x
for hexadecimal.
.El
.Pp
.Nm
is useful for identifying random binaries, among other things.
.Sh SEE ALSO
.Xr hexdump 1 ,
.Xr od 1
.Sh STANDARDS
The
.Nm
utility is compliant with the
.St -p1003.1-2008
specification.
.Pp
The flags
.Op Fl fmo
are extensions to that specification.
.Pp
Historic implementations of
.Nm
only search the initialized data portion of the object file.
This was reasonable as strings were normally stored there.
Given new compiler technology which installs strings in the
text portion of the object file, the default behavior was
changed.
.Sh HISTORY
The
.Nm
utility appeared in
.Bx 3.0 .
.Sh BUGS
The algorithm for identifying strings is extremely primitive.
In particular, machine code instructions on certain architectures
can resemble sequences of ASCII bytes, which
will fool the algorithm.