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awk:awk_variables [2020/05/06 18:31] – peterawk:awk_variables [2021/01/06 15:55] (current) – [FNR] peter
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 |BINMODE|Specifies use of “binary” mode for all file I/O.| |BINMODE|Specifies use of “binary” mode for all file I/O.|
 |CONVFMT|The conversion format for numbers, "%.6g", by default.| |CONVFMT|The conversion format for numbers, "%.6g", by default.|
 +|ENVIRON|Environment Variables.|
 |FIELDWIDTHS|A white-space separated list of field widths. When set the input is parsed into fields of fixed width, instead of using the value of the FS variable as the field separator.| |FIELDWIDTHS|A white-space separated list of field widths. When set the input is parsed into fields of fixed width, instead of using the value of the FS variable as the field separator.|
 +|FILENAME|Current filename.|
 |FNR|The input record number in the current input file.| |FNR|The input record number in the current input file.|
 |FPAT|A regular expression describing the contents of the fields in a record. When set the input is parsed into fields, where the fields match the regular expression, instead of using the value of the FS variable as the field separator.| |FPAT|A regular expression describing the contents of the fields in a record. When set the input is parsed into fields, where the fields match the regular expression, instead of using the value of the FS variable as the field separator.|
 |FS|The input field separator, a space by default.| |FS|The input field separator, a space by default.|
 |IGNORECASE|Controls the case-sensitivity of all regular expression and string operations.| |IGNORECASE|Controls the case-sensitivity of all regular expression and string operations.|
 +|LINT|Provides dynamic control of the –lint option.|
 |NF|The number of fields in the current input record.| |NF|The number of fields in the current input record.|
 |NR|The total number of input records seen so far.| |NR|The total number of input records seen so far.|
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 |OFS|The output field separator, a space by default.| |OFS|The output field separator, a space by default.|
 |ORS|The output record separator, by default a newline.| |ORS|The output record separator, by default a newline.|
 +|PROCINFO|Information about the process.|
 +|RLENGTH|The length of the string matched by the match function.|
 +|RSTART|The first position in the string matched by match function.|
 |RS|The input record separator, by default a newline.| |RS|The input record separator, by default a newline.|
 |RT|The record terminator.| |RT|The record terminator.|
 |SUBSEP|The character used to separate multiple subscripts in array elements, by default "\034".| |SUBSEP|The character used to separate multiple subscripts in array elements, by default "\034".|
 +|TEXTDOMAIN|The text domain of the AWK program.  For compatibility with GNU **gettext**.  The default value is "messages".|
 +
  
 ---- ----
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 It represents the index in ARGV of the current file being processed. It represents the index in ARGV of the current file being processed.
  
-<code bash>+<code awk>
 awk '{  awk '{ 
    print "ARGIND   = ", ARGIND; print "Filename = ", ARGV[ARGIND]     print "ARGIND   = ", ARGIND; print "Filename = ", ARGV[ARGIND] 
Line 95: Line 103:
 ARGV[3] = three ARGV[3] = three
 </code> </code>
 +----
 +
 +===== BINMODE =====
 +
 +It is used to specify binary mode for all file I/O on non-POSIX systems.
 +
 +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.
  
 ---- ----
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 Its default value is %.6g. Its default value is %.6g.
  
-<code bash>+<code awk>
 awk 'BEGIN { print "Conversion Format =", CONVFMT }' awk 'BEGIN { print "Conversion Format =", CONVFMT }'
 </code> </code>
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 **NOTE:**  To find names of other environment variables, use the **env** command. **NOTE:**  To find names of other environment variables, use the **env** command.
 </WRAP> </WRAP>
 +
 +----
 +
 +===== ERRNO =====
 +
 +A string indicates an error when a redirection fails for getline or if a close call fails.
 +
 +<code awk>
 +awk 'BEGIN { ret = getline < "junk.txt"; if (ret == -1) print "Error:", ERRNO }'
 +</code>
 +
 +returns:
 +
 +<code bash>
 +Error: No such file or directory
 +</code>
 +
 +----
 +
 +===== FIELDWIDTHS =====
 +
 +A space separated list of field widths variable is set, GAWK parses the input into fields of fixed width, instead of using the value of the FS variable as the field separator.
  
 ---- ----
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 <WRAP info> <WRAP info>
 **NOTE:** Please note that FILENAME is undefined in the BEGIN block. **NOTE:** Please note that FILENAME is undefined in the BEGIN block.
 +</WRAP>
 +
 +----
 +
 +===== FNR =====
 +
 +It is similar to NR, but relative to the current file.
 +
 +It is useful when AWK is operating on multiple files.
 +
 +It represents the number of the current record in the current file.
 +
 +<code bash>
 +echo -e "One Two\nOne Two Three\nOne Two Three Four" | awk 'FNR < 3'
 +</code>
 +
 +returns:
 +
 +<code>
 +One Two
 +One Two Three
 +</code>
 +
 +<WRAP info>
 +**NOTE:**  The Value of FNR resets with a new file.
 </WRAP> </WRAP>
  
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 FS =  $ FS =  $
 </code> </code>
 +
 +----
 +
 +===== IGNORECASE =====
 +
 +When this variable is set, GAWK becomes case-insensitive.
 +
 +<code awk>
 +awk 'BEGIN{IGNORECASE = 1} /peter/' test.txt
 +</code>
 +
 +returns:
 +
 +<code bash>
 +10   Peter     Terence    Roux        45
 +</code>
 +
 +<WRAP info>
 +**NOTE:**  If IGNORECASE does not work then try:
 +
 +<code bash>
 +awk 'tolower($0) ~ /peter/' test.txt
 +</code>
 +
 +</WRAP>
 +
 +----
 +
 +===== LINT =====
 +
 +It provides dynamic control of the **--lint** option from the GAWK program.
 +
 +When this variable is set, GAWK prints lint warnings.
 +
 +When assigned the string value fatal, lint warnings become fatal errors, exactly like **--lint=fatal**.
 +
 +<code awk>
 +awk 'BEGIN {LINT = 1; a}'
 +</code>
 +
 +returns:
 +
 +<code bash>
 +awk: cmd. line:1: warning: reference to uninitialized variable `a'
 +awk: cmd. line:1: warning: statement has no effect
 +</code>
 +
 +<WRAP info>
 +**NOTE:**  This only works with GAWK, not AWK.
 +</WRAP>
  
 ---- ----
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 One Two Three One Two Three
 </code> </code>
- 
----- 
- 
-===== FNR ===== 
- 
-It is similar to NR, but relative to the current file. 
- 
-It is useful when AWK is operating on multiple files. 
- 
-Value of FNR resets with a new file. 
  
 ---- ----
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 It represents the output format number and its default value is %.6g. It represents the output format number and its default value is %.6g.
  
-<code bash>+<code awk>
 awk 'BEGIN {print "OFMT = " OFMT}' awk 'BEGIN {print "OFMT = " OFMT}'
 </code> </code>
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 It represents the output field separator and its default value is space. It represents the output field separator and its default value is space.
  
-<code bash>+<code awk>
 awk 'BEGIN {print "OFS = " OFS}' | cat -vte awk 'BEGIN {print "OFS = " OFS}' | cat -vte
 </code> </code>
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 It represents the output record separator and its default value is newline. It represents the output record separator and its default value is newline.
  
-<code bash>+<code awk>
 awk 'BEGIN {print "ORS = " ORS}' | cat -vte awk 'BEGIN {print "ORS = " ORS}' | cat -vte
 </code> </code>
Line 267: Line 373:
 ORS = $ ORS = $
 $ $
 +</code>
 +
 +----
 +
 +===== PROCINFO =====
 +
 +This is an associative array containing information about the process, such as real and effective UID numbers, process ID number, and so on.
 +
 +<code awk>
 +awk 'BEGIN { print PROCINFO["pid"] }'
 +</code>
 +
 +returns:
 +
 +<code bash>
 +30510
 </code> </code>
  
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 AWK's match function searches for a given string in the input-string. AWK's match function searches for a given string in the input-string.
  
-<code bash>+<code awk>
 awk 'BEGIN { if (match("One Two Three", "re")) { print RLENGTH } }' awk 'BEGIN { if (match("One Two Three", "re")) { print RLENGTH } }'
 </code> </code>
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 It represents (input) record separator and its default value is newline. It represents (input) record separator and its default value is newline.
  
-<code bash>+<code awk>
 awk 'BEGIN {print "RS = " RS}' | cat -vte awk 'BEGIN {print "RS = " RS}' | cat -vte
 </code> </code>
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 It represents the first position in the string matched by match function. It represents the first position in the string matched by match function.
  
-<code bash>+<code awk>
 awk 'BEGIN { if (match("One Two Three", "Thre")) { print RSTART } }' awk 'BEGIN { if (match("One Two Three", "Thre")) { print RSTART } }'
 </code> </code>
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 It represents the separator character for array subscripts and its default value is \034. It represents the separator character for array subscripts and its default value is \034.
  
-<code bash>+<code awk>
 awk 'BEGIN { print "SUBSEP = " SUBSEP }' | cat -vte awk 'BEGIN { print "SUBSEP = " SUBSEP }' | cat -vte
 </code> </code>
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 It represents the entire input record. It represents the entire input record.
  
-<code bash>+<code awk>
 awk '{print $0}' test.txt awk '{print $0}' test.txt
 </code> </code>
Line 357: Line 479:
 48   Adam      Winter     Ridley      23 48   Adam      Winter     Ridley      23
 </file> </file>
 +
 +----
 +
 +===== TEXTDOMAIN =====
 +
 +It represents the text domain of the AWK program.
 +
 +It is used to find the localized translations for the program's strings.
 +
 +<code awk>
 +awk 'BEGIN { print TEXTDOMAIN }'
 +</code>
 +
 +returns:
 +
 +<code bash>
 +messages
 +</code>
 +
 +<WRAP info>
 +**NOTE:**  The above output shows English text due to en_GB locale.
 +</WRAP>
 +
  
 ---- ----
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 It represents the nth field in the current record where the fields are separated by FS. It represents the nth field in the current record where the fields are separated by FS.
  
-<code bash>+<code awk>
 awk '{print $2 "\t" $5}' test.txt awk '{print $2 "\t" $5}' test.txt
 </code> </code>
awk/awk_variables.1588789903.txt.gz · Last modified: 2020/07/15 09:30 (external edit)
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