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UNIX for Dummies Questions & Answers
UNIX basics
Post 302920668 by DGPickett on Friday 10th of October 2014 05:23:54 PM
10-10-2014
A Parameter is an Argument with a stuck up attitude? An Argument is a Parameter with a bad attitude? 
Yes, UNIX is an O/S, the variables and such come with languages, applications, the O/S kernel and libraries. UNIX is mostly written in C, or these days maybe C++, and comes with libraries that are most accessible in those languages. Other languages wrote interfaces to them. Since libraries are in execution or object code, any language can link to them and pass and receive data, sometimes with other real world side effects like writing a file.
The shell is a slightly more human friendly, interactive- and interpretation-oriented language. There are many variations on the shell.
Variables exist in the memory space of the application's process and in the UNIX kernel. They usually conform to datatypes of the common languages and CPU hardware, like the 4 byte or 32 bit 2's complement big-endian signed binary integer, or int. All memory and file space is alike until a context is thrown over it. If it is string or character data, still the glyphs you see when it is prints and the amount of space it takes is context-dependent: ASCII, EBCDIC, UNICODE, UTF-8, EUC, Latin-1, iso8859-1, . . . . Memory can have code and variables in it, as well as unallocated spaces. For a compiler or link loader, the code is also just data out of context. Most code is CPU-specific and somewhat O/S specific (object code), but some is for an interpreter like the shell (scripts or *codes) or to instruct a compiler (source code). Source code is text from humans that is compiled into object code for execution. Some programs can be executed directly, and others are just libraries of callable subroutines and other constants to assist runnable programs and each other. The UNIX kernel is the first loaded program at the bottom of memory by bootload, which serves all the running processes, some of which are part of the UNIX O/S.
Knowing the big picture keeps the snow level down. Everything runs on top of this, one way or the other. Every O/S is many ways similar.
Yes, UNIX is an O/S, the variables and such come with languages, applications, the O/S kernel and libraries. UNIX is mostly written in C, or these days maybe C++, and comes with libraries that are most accessible in those languages. Other languages wrote interfaces to them. Since libraries are in execution or object code, any language can link to them and pass and receive data, sometimes with other real world side effects like writing a file.
The shell is a slightly more human friendly, interactive- and interpretation-oriented language. There are many variations on the shell.
Variables exist in the memory space of the application's process and in the UNIX kernel. They usually conform to datatypes of the common languages and CPU hardware, like the 4 byte or 32 bit 2's complement big-endian signed binary integer, or int. All memory and file space is alike until a context is thrown over it. If it is string or character data, still the glyphs you see when it is prints and the amount of space it takes is context-dependent: ASCII, EBCDIC, UNICODE, UTF-8, EUC, Latin-1, iso8859-1, . . . . Memory can have code and variables in it, as well as unallocated spaces. For a compiler or link loader, the code is also just data out of context. Most code is CPU-specific and somewhat O/S specific (object code), but some is for an interpreter like the shell (scripts or *codes) or to instruct a compiler (source code). Source code is text from humans that is compiled into object code for execution. Some programs can be executed directly, and others are just libraries of callable subroutines and other constants to assist runnable programs and each other. The UNIX kernel is the first loaded program at the bottom of memory by bootload, which serves all the running processes, some of which are part of the UNIX O/S.
Knowing the big picture keeps the snow level down. Everything runs on top of this, one way or the other. Every O/S is many ways similar.
Last edited by DGPickett; 10-10-2014 at 06:31 PM..
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LEARN ABOUT OSF1
cp1250
code_page(5) File Formats Manual code_page(5) NAME
code_page, cp437, cp737, cp775, cp850, cp852, cp855, cp857, cp860, cp861, cp862, cp863, cp865, cp866, cp869, cp874, cp932, cp936, cp949, cp950, cp1250, cp1251, cp1252, cp1253, cp1254, cp1255, cp1256, cp1257, cp1258, dingbats, symbol - Coded character sets that are used on Mi- crosoft Windows and NT systems DESCRIPTION
Code pages are coded character sets that are used on Microsoft Windows, Windows 95, and NT systems. Just as there are different UNIX code- sets, there are different PC code pages, each supporting a particular set of character encodings. A Tru64 UNIX system supplies one locale, en_US.cp850, that directly supports a PC code-page format (MS-DOS Latin 1). For all other locales, data in code-page format is supported only through codeset converters. These converters can be run directly by users or by software or applications that exchange data between PC and Tru64 UNIX systems. Fonts and other kinds of character support are available only for the native UNIX codeset to which a code page can be converted. See the i18n_intro(5) reference page for introductory information on locales and codesets. See the iconv_intro(5) reference page for an introduction to codeset conversion and the name format and location of codeset con- verters. The following table lists and describes the code pages that have conversion support on a Tru64 UNIX system. An asterisk (*) follows the names of code pages that include support for the Euro currency sign (C=). ------------------------------------------------------ Code Page Description ------------------------------------------------------ cp437 MS-DOS United States cp737 Greek cp775 Baltic languages (1) cp850 MS-DOS Multilingual (Latin-1) cp852 MS-DOS Slavic (Latin-2) cp855 IBM Cyrillic cp857 IBM Turkish cp860 MS-DOS Portuguese cp861 MS-DOS Icelandic cp862 Hebrew cp863 MS-DOS Canadian French cp865 MS-DOS Nordic languages cp866 MS-DOS Russian cp869 IBM Modern Greek cp874 * MS-DOS Thai cp932 Japanese cp936 Chinese (People's Republic of China) cp949 Korean cp950 Chinese (Hong Kong) cp1250 * Windows Latin-2 cp1251 * Windows Cyrillic cp1252 * Windows Latin-1 cp1253 * Windows Greek cp1254 * Windows Turkish cp1255 * Windows Hebrew cp1256 * Windows Arabic cp1257 * Windows Baltic (1) cp1258 * Windows Vietnamese dingbats Microsoft dingbat characters symbol Microsoft miscellaneous symbol characters ------------------------------------------------------ (1) Baltic languages include Estonian, Latvian, and Lithuanian. (2) Latin-2 languages include Albanian, Croatian, Czech, Faeroese, Hungarian, Polish, Romanian, Latin Serbian, Slovak, and Slovenian. (3) Cyrillic languages include Byelorussian, Bulgarian, and Russian. In all cases, a code page can be converted to and from the UCS-2, UCS-4, and UTF-8 codesets. In addition, some code pages can be converted directly to ISO codesets as shown in the following table, although some data loss may occur. ------------------------------------------ Code Page Can Be Converted Directly to: ------------------------------------------ cp437 ISO8859-1 cp737 ISO8859-7 cp775 ISO8859-4 cp850 ISO8859-1 cp852 ISO8859-2 cp855 ISO8859-5 cp857 ISO8859-9 cp860 ISO8859-1 cp861 ISO8859-1 cp862 ISO8859-8 cp863 ISO8859-1 cp865 ISO8859-1 cp866 ISO8859-5 cp869 ISO8859-7 cp874 TACTIS cp1252 ISO8859-1, ISO8859-15 ------------------------------------------ See Unicode(5) for information about UCS-2, UCS-4, and UTF-8. Reference pages for UNIX implementations of the ISO codesets have the name format iso8859-number(5). For Traditional Chinese and Japanese, there are no codeset converters whose names include the name of a code page because identical charac- ter encoding is provided in existing UNIX codesets. For Traditional Chinese, character encoding in PC code-page format (cp950) is identical to that in the Big-5 (big5) codeset. For Japanese, character encoding in PC code-page format (cp932) is identical to that in the Shift JIS (SJIS) codeset. Therefore, the codeset converters whose names include big5 and SJIS can be used to convert data in and out of PC code-page format for the supported languages. Caution for Conversion of Korean and Simplified Chinese Conversion of text that starts out in code-page format (cp949) to the DEC Korean (deckorean) codeset may result in loss of data. All of the Tru64 UNIX codeset equivalents for cp949 support all the Hanja and miscellaneous characters also supported by the code page. However, only the UCS-2, UCS-4, and UTF-8 codesets support the complete set of Hangul characters supported by the cp949 code page. The deckorean codeset supports only a subset of these Hangul characters. Therefore, if data is converted from cp949 format to UCS-2, UCS-4, or UTF-8, no data is lost. However, if the data is then converted from UCS-2, UCS-4, or UTF-8 to deckorean, the unsupported Hangul characters will be lost. The DEC Hanzi (dechanzi) codeset uses the same encoding format as the PC code page used for Simplified Chinese (cp936) but does not support all the characters supported by the code page. Therefore, you can use converters with dechanzi in the converter name to convert text to and from cp936 format, but the operation may result in some loss of data. SEE ALSO
Commands: iconv(1) Functions: iconv(3), iconv_close(3), iconv_open(3) Others: i18n_intro(5), iconv_intro(5), iso8859-1(5), iso8859-2(5), iso8859-4(5), iso8859-5(5), iso8859-7(5), iso8859-8(5), iso8859-15(5), Unicode(5) code_page(5)