найти строки для печати в файлах (find printable strings in files)
Пролог (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.
Имя (Name)
strings — find printable strings in files
Синопсис (Synopsis)
strings [-a] [-t format] [-n number] [file...]
Описание (Description)
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.
Параметры (Options)
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.
Операнды (Operands)
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.
Стандартный ввод (Stdin)
See the INPUT FILES section.
Входные файлы (Input files)
The input files named by the utility arguments or the standard
input shall be regular files of any format.
Переменные окружения (Environment variables)
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.
Асинхронные события (Asynchronous events)
Default.
Стандартный вывод (Stdout)
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>
Стандартный вывод сообщений (Stderr)
The standard error shall be used only for diagnostic messages.
Выходные файлы (Output files)
None.
Расширенное описание (Extended description)
None.
Статус выхода (Exit)
The following exit values shall be returned:
0 Successful completion.
>0 An error occurred.
Последствия ошибок (Consequences of errors)
Default.
The following sections are informative.
Использование в приложениях (Application usage)
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.
Примеры (Examples)
None.
Обоснование (Rationale)
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.
Будущие направления (Future directions)
None.
Смотри также (See also)
localedef(1p), nm(1p)
The Base Definitions volume of POSIX.1‐2017, Chapter 8,
Environment Variables, Section 12.2, Utility Syntax Guidelines
