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diff --git a/coreutils-5.3.0-bin/man/cat1p/awk.1p.txt b/coreutils-5.3.0-bin/man/cat1p/awk.1p.txt new file mode 100644 index 0000000..a173621 --- /dev/null +++ b/coreutils-5.3.0-bin/man/cat1p/awk.1p.txt @@ -0,0 +1,301 @@ +AWK(1P) POSIX Programmer's Manual AWK(1P) + + + +PROLOG + This manual page is part of the POSIX Programmer's Man- + ual. 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. + +NAME + awk - pattern scanning and processing language + +SYNOPSIS + awk [-F ERE][-v assignment] ... program [argument ...] + + awk [-F ERE] -f progfile ... [-v assignment] ...[argu- + ment ...] + + +DESCRIPTION + The awk utility shall execute programs written in the + awk programming language, which is specialized for tex- + tual data manipulation. An awk program is a sequence of + patterns and corresponding actions. When input is read + that matches a pattern, the action associated with that + pattern is carried out. + + Input shall be interpreted as a sequence of records. By + default, a record is a line, less its terminating <new- + line>, but this can be changed by using the RS built-in + variable. Each record of input shall be matched in turn + against each pattern in the program. For each pattern + matched, the associated action shall be executed. + + The awk utility shall interpret each input record as a + sequence of fields where, by default, a field is a + string of non- <blank>s. This default white-space field + delimiter can be changed by using the FS built-in vari- + able or -F ERE. The awk utility shall denote the first + field in a record $1, the second $2, and so on. The sym- + bol $0 shall refer to the entire record; setting any + other field causes the re-evaluation of $0. Assigning to + $0 shall reset the values of all other fields and the NF + built-in variable. + +OPTIONS + The awk utility shall conform to the Base Definitions + volume of IEEE Std 1003.1-2001, Section 12.2, Utility + Syntax Guidelines. + + The following options shall be supported: + + -F ERE + Define the input field separator to be the + extended regular expression ERE, before any input + is read; see Regular Expressions . + + -f progfile + Specify the pathname of the file progfile con- + taining an awk program. If multiple instances of + this option are specified, the concatenation of + the files specified as progfile in the order + specified shall be the awk program. The awk pro- + gram can alternatively be specified in the com- + mand line as a single argument. + + -v assignment + The application shall ensure that the assignment + argument is in the same form as an assignment + operand. The specified variable assignment shall + occur prior to executing the awk program, includ- + ing the actions associated with BEGIN patterns + (if any). Multiple occurrences of this option can + be specified. + + +OPERANDS + The following operands shall be supported: + + program + If no -f option is specified, the first operand + to awk shall be the text of the awk program. The + application shall supply the program operand as a + single argument to awk. If the text does not end + in a <newline>, awk shall interpret the text as + if it did. + + argument + Either of the following two types of argument can + be intermixed: + + file + A pathname of a file that contains the input to + be read, which is matched against the set of pat- + terns in the program. If no file operands are + specified, or if a file operand is '-', the stan- + dard input shall be used. + + assignment + An operand that begins with an underscore or + alphabetic character from the portable character + set (see the table in the Base Definitions volume + of IEEE Std 1003.1-2001, Section 6.1, Portable + Character Set), followed by a sequence of under- + scores, digits, and alphabetics from the portable + character set, followed by the '=' character, + shall specify a variable assignment rather than a + pathname. The characters before the '=' represent + the name of an awk variable; if that name is an + awk reserved word (see Grammar ) the behavior is + undefined. The characters following the equal + sign shall be interpreted as if they appeared in + the awk program preceded and followed by a dou- + ble-quote ( ' )' character, as a STRING token + (see Grammar ), except that if the last character + is an unescaped backslash, it shall be inter- + preted as a literal backslash rather than as the + first character of the sequence "\"" . The vari- + able shall be assigned the value of that STRING + token and, if appropriate, shall be considered a + numeric string (see Expressions in awk ), the + variable shall also be assigned its numeric + value. Each such variable assignment shall occur + just prior to the processing of the following + file, if any. Thus, an assignment before the + first file argument shall be executed after the + BEGIN actions (if any), while an assignment after + the last file argument shall occur before the END + actions (if any). If there are no file arguments, + assignments shall be executed before processing + the standard input. + + + +STDIN + The standard input shall be used only if no file + operands are specified, or if a file operand is '-' ; + see the INPUT FILES section. If the awk program contains + no actions and no patterns, but is otherwise a valid awk + program, standard input and any file operands shall not + be read and awk shall exit with a return status of zero. + +INPUT FILES + Input files to the awk program from any of the following + sources shall be text files: + + * Any file operands or their equivalents, achieved by + modifying the awk variables ARGV and ARGC + + + * Standard input in the absence of any file operands + + + * Arguments to the getline function + + + Whether the variable RS is set to a value other than a + <newline> or not, for these files, implementations shall + support records terminated with the specified separator + up to {LINE_MAX} bytes and may support longer records. + + If -f progfile is specified, the application shall + ensure that the files named by each of the progfile + option-arguments are text files and their concatenation, + in the same order as they appear in the arguments, is an + awk program. + +ENVIRONMENT VARIABLES + The following environment variables shall affect the + execution of awk: + + LANG Provide a default value for the internationaliza- + tion 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 cate- + gories.) + + LC_ALL If set to a non-empty string value, override the + values of all the other internationalization + variables. + + LC_COLLATE + Determine the locale for the behavior of ranges, + equivalence classes, and multi-character collat- + ing elements within regular expressions and in + comparisons of string values. + + 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), + the behavior of character classes within regular + expressions, the identification of characters as + letters, and the mapping of uppercase and lower- + case characters for the toupper and tolower func- + tions. + + LC_MESSAGES + Determine the locale that should be used to + affect the format and contents of diagnostic mes- + sages written to standard error. + + LC_NUMERIC + Determine the radix character used when inter- + preting numeric input, performing conversions + between numeric and string values, and formatting + numeric output. Regardless of locale, the period + character (the decimal-point character of the + POSIX locale) is the decimal-point character rec- + ognized in processing awk programs (including + assignments in command line arguments). + + NLSPATH + Determine the location of message catalogs for + the processing of LC_MESSAGES . + + PATH Determine the search path when looking for com- + mands executed by system(expr), or input and out- + put pipes; see the Base Definitions volume of + IEEE Std 1003.1-2001, Chapter 8, Environment + Variables. + + + In addition, all environment variables shall be visible + via the awk variable ENVIRON. + +ASYNCHRONOUS EVENTS + Default. + +STDOUT + The nature of the output files depends on the awk pro- + gram. + +STDERR + The standard error shall be used only for diagnostic + messages. + +OUTPUT FILES + The nature of the output files depends on the awk pro- + gram. + +EXTENDED DESCRIPTION + Overall Program Structure + An awk program is composed of pairs of the form: + + + pattern { action } + + Either the pattern or the action (including the enclos- + ing brace characters) can be omitted. + + A missing pattern shall match any record of input, and a + missing action shall be equivalent to: + + + { print } + + Execution of the awk program shall start by first exe- + cuting the actions associated with all BEGIN patterns in + the order they occur in the program. Then each file + operand (or standard input if no files were specified) + shall be processed in turn by reading data from the file + until a record separator is seen ( <newline> by + default). Before the first reference to a field in the + record is evaluated, the record shall be split into + fields, according to the rules in Regular Expressions, + using the value of FS that was current at the time the + record was read. Each pattern in the program then shall + be evaluated in the order of occurrence, and the action + associated with each pattern that matches the current + record executed. The action for a matching pattern shall + be executed before evaluating subsequent patterns. + Finally, the actions associated with all END patterns + shall be executed in the order they occur in the pro- + gram. + + Expressions in awk + Expressions describe computations used in patterns and + actions. In the following table, valid expression + operations are given in groups from highest precedence + first to lowest precedence last, with equal-precedence + operators grouped between horizontal lines. In expres- + sion evaluation, where the grammar is formally ambigu- + ous, higher precedence operators shall be evaluated + before lower precedence operators. In this table expr, + expr1, expr2, and expr3 represent any expression, while + lvalue represents any entity that can be assigned to + (that is, on the left side of an assignment operator). + The precise syntax of expressions is given in Grammar . + + Table: Expressions in Decreasing Precedence in awk + + + + +IEEE/The Open Group 2003 AWK(1P) |