2010年（20）
分类： LINUX
2010-04-27 03:27:53
.-----------------------------------------------------------------------.
| |
| AWK Cheat Sheet |
| |
'-----------------------------------------------------------------------'
| Peteris Krumins (peter@catonmat.net), 2007.08.22 |
| - good coders code, great reuse |
'-----------------------------------------------------------------------'
===================== Predefined Variable Summary =====================
.-------------+-----------------------------------.---------------------.
| | | Support: |
| Variable | Description '-----.-------.-------'
| | | AWK | NAWK | GAWK |
'-------------+-----------------------------------+-----+-------+-------'
| FS | Input Field Separator, a space by | + | + | + |
| | default. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| OFS | Output Field Separator, a space | + | + | + |
| | by default. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| NF | The Number of Fields in the | + | + | + |
| | current input record. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| NR | The total Number of input Records | + | + | + |
| | seen so far. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| RS | Record Separator, a newline by | + | + | + |
| | default. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| ORS | Output Record Separator, a | + | + | + |
| | newline by default. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| FILENAME | The name of the current input | | | |
| | file. If no files are specified | | | |
| | on the command line, the value of | | | |
| | FILENAME is "-". However, | + | + | + |
| | FILENAME is undefined inside the | | | |
| | BEGIN block (unless set by | | | |
| | getline). | | | |
'-------------+-----------------------------------+-----+-------+-------'
| ARGC | The number of command line | | | |
| | arguments (does not include | | | |
| | options to gawk, or the program | - | + | + |
| | source). Dynamically changing the | | | |
| | contents of ARGV control the | - | + | + |
| | files used for data. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| ARGV | Array of command line arguments. | | | |
| | The array is indexed from 0 to | - | + | + |
| | ARGC - 1. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| ARGIND | The index in ARGV of the current | - | - | + |
| | file being processed. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| BINMODE | On non-POSIX systems, specifies | | | |
| | use of "binary" mode for all file | | | |
| | I/O.Numeric values of 1, 2, or 3, | | | |
| | specify that input files, output | | | |
| | files, or all files, respectively,| | | |
| | should use binary I/O. String | | | |
| | values of "r", or "w" specify | - | - | + |
| | that input files, or output files,| | | |
| | respectively, should use binary | | | |
| | I/O. String values of "rw" or | | | |
| | "wr" specify that all files | | | |
| | should use binary I/O. Any other | | | |
| | string value is treated as "rw", | | | |
| | but generates a warning message. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| CONVFMT | The CONVFMT variable is used to | | | |
| | specify the format when | - | - | + |
| | converting a number to a string. | | | |
| | Default: "%.6g" | | | |
'-------------+-----------------------------------+-----+-------+-------'
| ENVIRON | An array containing the values | - | - | + |
| | of the current environment. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| ERRNO | If a system error occurs either | | | |
| | doing a redirection for getline, | | | |
| | during a read for getline, or | | | |
| | during a close(), then ERRNO will | - | - | + |
| | contain a string describing the | | | |
| | error. The value is subject to | | | |
| | translation in non-English locales. | | |
'-------------+-----------------------------------+-----+-------+-------'
| FIELDWIDTHS | A white-space separated list of | | | |
| | fieldwidths. When set, gawk | | | |
| | parses the input into fields of | - | - | + |
| | fixed width, instead of using the | | | |
| | value of the FS variable as the | | | |
| | field separator. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| FNR | Contains number of lines read, | - | + | + |
| | but is reset for each file read. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| IGNORECASE | Controls the case-sensitivity of | | | |
| | all regular expression and string | | | |
| | operations. If IGNORECASE has a | | | |
| | non-zero value, then string | | | |
| | comparisons and pattern matching | | | |
| | in rules, field splitting | | | |
| | with FS, record separating | | | |
| | with RS, regular expression | | | |
| | matching with ~ and !~, and the | - | - | + |
| | gensub(), gsub(), index(), | | | |
| | match(), split(), and sub() | | | |
| | built-in functions all ignore | | | |
| | case when doing regular | | | |
| | expression operations. | | | |
| | NOTE: Array subscripting is not | | | |
| | affected. However, the asort() | | | |
| | and asorti() functions are | | | |
| | affected | | | |
'-------------+-----------------------------------+-----+-------+-------'
| LINT | Provides dynamic control of the | | | |
| | --lint option from within an AWK | - | - | + |
| | program. When true, gawk prints | | | |
| | lint warnings. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| OFMT | The default output format for | - | + | + |
| | numbers. Default: "%.6g" | | | |
'-------------+-----------------------------------+-----+-------+-------'
| PROCINFO | The elements of this array | | | |
| | provide access to information | | | |
| | about the running AWK program. | | | |
| | PROCINFO["egid"]: | | | |
| | the value of the getegid(2) | | | |
| | system call. | | | |
| | PROCINFO["euid"]: | | | |
| | the value of the geteuid(2) | | | |
| | system call. | | | |
| | PROCINFO["FS"]: | | | |
| | "FS" if field splitting with FS | | | |
| | is in effect, or "FIELDWIDTHS" | | | |
| | if field splitting with | | | |
| | FIELDWIDTHS is in effect. | | | |
| | PROCINFO["gid"]: | - | - | + |
| | the value of the getgid(2) system | | | |
| | call. | | | |
| | PROCINFO["pgrpid"]: | | | |
| | the process group ID of the | | | |
| | current process. | | | |
| | PROCINFO["pid"]: | | | |
| | the process ID of the current | | | |
| | process. | | | |
| | PROCINFO["ppid"]: | | | |
| | the parent process ID of the | | | |
| | current process. | | | |
| | PROCINFO["uid"] | | | |
| | the value of the getuid(2) system | | | |
| | call. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| RT | The record terminator. Gawk sets | | | |
| | RT to the input text that matched | - | - | + |
| | the character or regular | | | |
| | expression specified by RS. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| RSTART | The index of the first character | - | + | + |
| | matched by match(); 0 if no match.| | | |
'-------------+-----------------------------------+-----+-------+-------'
| RLENGTH | The length of the string matched | - | + | + |
| | by match(); -1 if no match. | | | |
'-------------+-----------------------------------+-----+-------+-------'
| SUBSEP | The character used to separate | | | |
| | multiple subscripts in array | | | |
| | elements.Default: "\034" | - | + | + |
| | (non-printable character, | | | |
| | dec: 28, hex: 1C) | | | |
'-------------+-----------------------------------+-----+-------+-------'
| TEXTDOMAIN | The text domain of the AWK | | | |
| | program; used to find the | - | - | + |
| | localized translations for the | | | |
| | program's strings. | | | |
'-------------'-----------------------------------'-----'-------'-------'
============================ I/O Statements ===========================
.---------------------.-------------------------------------------------.
| | |
| Statement | Description |
| | |
'---------------------+-------------------------------------------------'
| close(file [, how]) | Close file, pipe or co-process. The optional |
| | how should only be used when closing one end of |
| | a two-way pipe to a co-process. It must be a |
| | string value, either "to" or "from". |
'---------------------+-------------------------------------------------'
| getline | Set $0 from next input record; set NF, NR, FNR. |
| | Returns 0 on EOF and
