.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved 
.TH "STRINGS" 1P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\" strings 
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
.SH NAME
strings \- find printable strings in files
.SH SYNOPSIS
.LP
\fBstrings\fP \fB[\fP\fB-a\fP\fB][\fP\fB-t\fP \fIformat\fP\fB][\fP\fB-n\fP
\fInumber\fP\fB][\fP\fIfile\fP\fB...\fP\fB]\fP\fB\fP
.SH DESCRIPTION
.LP
The \fIstrings\fP utility shall look for printable strings in regular
files and shall write those strings to standard output. A
printable string is any sequence of four (by default) or more printable
characters terminated by a <newline> or NUL
character. Additional implementation-defined strings may be written;
see \fIlocaledef\fP.
.SH OPTIONS
.LP
The \fIstrings\fP utility shall conform to the Base Definitions volume
of IEEE\ Std\ 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
.LP
The following options shall be supported:
.TP 7
\fB-a\fP
Scan files in their entirety. If \fB-a\fP is not specified, it is
implementation-defined what portion of each file is scanned
for strings.
.TP 7
\fB-n\ \fP \fInumber\fP
Specify the minimum string length, where the \fInumber\fP argument
is a positive decimal integer. The default shall be 4.
.TP 7
\fB-t\ \fP \fIformat\fP
Write each string preceded by its byte offset from the start of the
file. The format shall be dependent on the single character
used as the \fIformat\fP option-argument: 
.TP 7
\fBd\fP
.RS
The offset shall be written in decimal.
.RE
.TP 7
\fBo\fP
.RS
The offset shall be written in octal.
.RE
.TP 7
\fBx\fP
.RS
The offset shall be written in hexadecimal.
.RE
.sp
.sp
.SH OPERANDS
.LP
The following operand shall be supported:
.TP 7
\fIfile\fP
A pathname of a regular file to be used as input. If no \fIfile\fP
operand is specified, the \fIstrings\fP utility shall read
from the standard input.
.sp
.SH STDIN
.LP
See the INPUT FILES section.
.SH INPUT FILES
.LP
The input files named by the utility arguments or the standard input
shall be regular files of any format.
.SH ENVIRONMENT VARIABLES
.LP
The following environment variables shall affect the execution of
\fIstrings\fP:
.TP 7
\fILANG\fP
Provide a default value for the internationalization variables that
are unset or null. (See the Base Definitions volume of
IEEE\ Std\ 1003.1-2001, Section 8.2, Internationalization Variables
for
the precedence of internationalization variables used to determine
the values of locale categories.)
.TP 7
\fILC_ALL\fP
If set to a non-empty string value, override the values of all the
other internationalization variables.
.TP 7
\fILC_CTYPE\fP
Determine the locale for the interpretation of sequences of bytes
of text data as characters (for example, single-byte as
opposed to multi-byte characters in arguments and input files) and
to identify printable strings.
.TP 7
\fILC_MESSAGES\fP
Determine the locale that should be used to affect the format and
contents of diagnostic messages written to standard
error.
.TP 7
\fINLSPATH\fP
Determine the location of message catalogs for the processing of \fILC_MESSAGES
\&.\fP 
.sp
.SH ASYNCHRONOUS EVENTS
.LP
Default.
.SH STDOUT
.LP
Strings found shall be written to the standard output, one per line.
.LP
When the \fB-t\fP option is not specified, the format of the output
shall be:
.sp
.RS
.nf

\fB"%s", <\fP\fIstring\fP\fB>
\fP
.fi
.RE
.LP
With the \fB-t\ o\fP option, the format of the output shall be:
.sp
.RS
.nf

\fB"%o %s", <\fP\fIbyte offset\fP\fB>, <\fP\fIstring\fP\fB>
\fP
.fi
.RE
.LP
With the \fB-t\ x\fP option, the format of the output shall be:
.sp
.RS
.nf

\fB"%x %s", <\fP\fIbyte offset\fP\fB>, <\fP\fIstring\fP\fB>
\fP
.fi
.RE
.LP
With the \fB-t\ d\fP option, the format of the output shall be:
.sp
.RS
.nf

\fB"%d %s", <\fP\fIbyte offset\fP\fB>, <\fP\fIstring\fP\fB>
\fP
.fi
.RE
.SH STDERR
.LP
The standard error shall be used only for diagnostic messages.
.SH OUTPUT FILES
.LP
None.
.SH EXTENDED DESCRIPTION
.LP
None.
.SH EXIT STATUS
.LP
The following exit values shall be returned:
.TP 7
\ 0
Successful completion.
.TP 7
>0
An error occurred.
.sp
.SH CONSEQUENCES OF ERRORS
.LP
Default.
.LP
\fIThe following sections are informative.\fP
.SH APPLICATION USAGE
.LP
By default the data area (as opposed to the text, "bss", or header
areas) of a binary executable file is scanned.
Implementations document which areas are scanned.
.LP
Some historical implementations do not require NUL or <newline> terminators
for strings to permit those languages that do
not use NUL as a string terminator to have their strings written.
.SH EXAMPLES
.LP
None.
.SH RATIONALE
.LP
Apart from rationalizing the option syntax and slight difficulties
with object and executable binary files, \fIstrings\fP is
specified to match historical practice closely. The \fB-a\fP and \fB-n\fP
options were introduced to replace the non-conforming
\fB-\fP and \fB-\fP \fInumber\fP options.
.LP
The \fB-o\fP option historically means different things on different
implementations. Some use it to mean " \fIoffset\fP in
decimal", while others use it as " \fIoffset\fP in octal". Instead
of trying to decide which way would be least objectionable,
the \fB-t\fP option was added. It was originally named \fB-O\fP to
mean "offset", but was changed to \fB-t\fP to be consistent
with \fIod\fP.
.LP
The ISO\ C standard function \fIisprint\fP() is restricted to a domain
of
\fBunsigned char\fP. This volume of IEEE\ Std\ 1003.1-2001 requires
implementations to write strings as defined by the
current locale.
.SH FUTURE DIRECTIONS
.LP
None.
.SH SEE ALSO
.LP
\fIlocaledef\fP, \fInm\fP
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .