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PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
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STRINGS(1P) POSIX Programmer's Manual STRINGS(1P)
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.
strings — find printable strings in files
strings [-a] [-t format] [-n number] [file...]
The strings 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
localedef.
If the first argument is '-', the results are unspecified.
The strings utility shall conform to the Base Definitions volume
of POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines, except
for the unspecified usage of '-'.
The following options shall be supported:
-a Scan files in their entirety. If -a is not specified, it
is implementation-defined what portion of each file is
scanned for strings.
-n number Specify the minimum string length, where the number
argument is a positive decimal integer. The default
shall be 4.
-t format 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 format option-argument:
d The offset shall be written in decimal.
o The offset shall be written in octal.
x The offset shall be written in hexadecimal.
The following operand shall be supported:
file A pathname of a regular file to be used as input. If no
file operand is specified, the strings utility shall
read from the standard input.
See the INPUT FILES section.
The input files named by the utility arguments or the standard
input shall be regular files of any format.
The following environment variables shall affect the execution of
strings:
LANG Provide a default value for the internationalization
variables that are unset or null. (See the Base
Definitions volume of POSIX.1‐2017, Section 8.2,
Internationalization Variables for the precedence of
internationalization variables used to determine the
values of locale categories.)
LC_ALL If set to a non-empty string value, override the values
of all the other internationalization variables.
LC_CTYPE 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.
LC_MESSAGES
Determine the locale that should be used to affect the
format and contents of diagnostic messages written to
standard error.
NLSPATH Determine the location of message catalogs for the
processing of LC_MESSAGES.
Default.
Strings found shall be written to the standard output, one per
line.
When the -t option is not specified, the format of the output
shall be:
"%s", <string>
With the -t o option, the format of the output shall be:
"%o %s", <byte offset>, <string>
With the -t x option, the format of the output shall be:
"%x %s", <byte offset>, <string>
With the -t d option, the format of the output shall be:
"%d %s", <byte offset>, <string>
The standard error shall be used only for diagnostic messages.
None.
None.
The following exit values shall be returned:
0 Successful completion.
>0 An error occurred.
Default.
The following sections are informative.
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.
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.
None.
Apart from rationalizing the option syntax and slight difficulties
with object and executable binary files, strings is specified to
match historical practice closely. The -a and -n options were
introduced to replace the non-conforming - and -number options.
These options are no longer specified by POSIX.1‐2008 but may be
present in some implementations.
The -o option historically means different things on different
implementations. Some use it to mean ``offset in decimal'', while
others use it as ``offset in octal''. Instead of trying to decide
which way would be least objectionable, the -t option was added.
It was originally named -O to mean ``offset'', but was changed to
-t to be consistent with od.
The ISO C standard function isprint() is restricted to a domain of
unsigned char. This volume of POSIX.1‐2017 requires
implementations to write strings as defined by the current locale.
None.
localedef(1p), nm(1p)
The Base Definitions volume of POSIX.1‐2017, Chapter 8,
Environment Variables, Section 12.2, Utility Syntax Guidelines
Portions of this text are reprinted and reproduced in electronic
form from IEEE Std 1003.1-2017, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The
Open Group Base Specifications Issue 7, 2018 Edition, Copyright
(C) 2018 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 .
Any typographical or formatting errors that appear in this page
are most likely to have been introduced during the conversion of
the source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2017 STRINGS(1P)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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