Lines and Strings

Line Breaks

EOL; LF

Matches the single line feed character (ASCII 0xa).

CR

Matches single carriage return character (ASCII 0xd).

EOLWIN

Matches two characters: line feed followed by the carriage return (ASCII 0xd 0xa)

Line Data

LD, LDATA

Matches any characters until the next non-optional matcher in the scope of a line.

Example 1

Parsing lines ending with single line-feed character (i.e a *NIX text file). Note that line endings are marked with 'n' for clarity:

plaintextcopydownload
Red fox jumps over lazy dog\n
\n
The end\n

The following pattern extracts the content of the entire line - i.e matches any character until the line-feed:

plaintextcopydownload
LD:line EOL

Results in the first and third lines being parsed out. The second line fails to parse because LD matcher encountered an end of line before required minimum matching count (default 1):

Example 2

Extracting username field from a CSV file:

plaintextcopydownload
2016-01-03 00:13:28,110.188.4.216,forerequest,200
2016-01-06 06:35:24,48.242.116.66,unrioting,200
2016-01-05 11:49:01,223.11.158.94,ribassano,404

plaintextcopydownload
TIMESTAMP:date_time ','
IPADDR:ip           ','
LD:username         ','
LD EOL;

where:

1. extracts time and date, followed by field separator ','
2. extracts ip-address, followed by field separator ','
3. extracts username by matching any characters until field separator ','
4. matches but does not extract any character for the rest of the line

Results:

Multiline Data

DATA

Matches any characters until the next non-optional matcher of pattern expression.

Example

Parsing stack trace records, laid over multiple lines and terminated by an empty line - i.e two consecutive line breaks:

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2015.10.03 16:32:51.371 +0000     ERROR   com.dt.webconsole.jsp.data.SQLTimeSeriesCache -- SQLTimeSeries remote fetch failed
org.postgresql.util.PSQLException: Connection refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
        at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:66)
        at org.postgresql.jdbc2.AbstractJdbc2Connection.<init>(AbstractJdbc2Connection.java:125)
        at org.postgresql.jdbc3.AbstractJdbc3Connection.<init>(AbstractJdbc3Connection.java:30)
        at org.postgresql.jdbc3g.AbstractJdbc3gConnection.<init>(AbstractJdbc3gConnection.java:22)
        at org.postgresql.jdbc4.AbstractJdbc4Connection.<init>(AbstractJdbc4Connection.java:30)
        at org.postgresql.jdbc4.Jdbc4Connection.<init>(Jdbc4Connection.java:24)
        at org.postgresql.Driver.makeConnection(Driver.java:393)
        at org.postgresql.Driver.connect(Driver.java:267)

2015-10-03 19:33:47.422 +0000   WARN    main    com.dt.wgui.WGUIMain        Log processing started in /Users/user/dt, listening http://localhost:8390/, pid: 11364@abcdef

plaintextcopydownload
DATA:record (EOL EOL)

Quoted Strings

SQS

Matches string enclosed between single quotes (ASCII 0x27). Any single quote inside the string must be escaped by backslash character "".

Example

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'Ay caramba!'

'Homer said: d\'oh!'

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SQS:sq_string EOL

Result:

Parsing the empty second line fails since SQS expects by default at least one character matching.

DQS

Matches string enclosed between double-quote characters (ASCII 0x22). Any double quote inside the string must be escaped by a backslash character (ASCII 0x5c).

Example

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"Red fox jumps over lazy dog"
"Red fox jumps over "lazy" dog"

plaintextcopydownload
DQS:dq_string EOL

Result:

CSVSQS

Matches string enclosed between single quotes (ASCII 0x27). Any single quote inside the string must be escaped by single quote character (CSV style).

Example

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'Red fox jumps over lazy dog'
'Red fox jumps over ''lazy'' dog'

plaintextcopydownload
CSVSQS:csvsq_string EOL

Result:

CSVDQS

Matches string enclosed between double-quote characters (ASCII 0x22). Any double quote inside the string must be escaped by double-quote character (CSV style).

Example

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"Red fox jumps over lazy dog"
"Red fox jumps over ""lazy"" dog"

plaintextcopydownload
CSVSQS:csvsq_string EOL

Result:

Character Group

[ char ... ]

Matches a single character out of several in a defined group. Simply place the characters you want to match between square brackets.

Characters can also be expressed as ranges, for instance [0-9] matches any digit from 0 to 9. Negating is supported by placing a caret "^" or an exclamation mark "!" before characters.

In case you want to match a square bracket character, it must be escaped by a preceding backslash character(0x5c ASCII ).

Use a quantifier if you want to match more than single characters.

The syntax is compatible with Regular Expression Character Class.

Character group allows matching strings with specific characters (as opposed to LD or DATA which matches any characters).

Example

Extracting username field, which is expected to consist of lowercase letters a to z and numbers, with minimum length of 4 characters and a maximum length of 15 characters:

plaintextcopydownload
2016-01-03 00:13:28,110.188.4.216,forerequest,200
2016-01-06 06:35:24,48.242.116.66,02rioting,200
2016-01-05 11:49:01,223.11.158.94,ribassano,404

plaintextcopydownload
TIMESTAMP:date_time  ','
IPADDR:ip            ','
[a-z]{4,15}:username ','
LD EOL;

where:

1. extracts time and date, followed by field separator ','
2. extracts ip-address, followed by field separator ','
3. extracts username by matching characters a to z, min 4, max 10 times, followed by field separator ','
4. matches but does not extract any character for the rest of the line

Results in all lines parsed into fields date_time, ip, username.

POSIX Character Classes

Match one or more character corresponding to any of the characters in its defined group.

ALNUM

POSIX notation: [:alnum:]

Matches alphanumeric characters a-z; A-Z; 0-9

ALPHA

[:alpha:] Matches alphabetic characters a-z; A-Z

BLANK

[:blank:] Matches space (0x20) and tab (0x9) characters

CNTRL

[:cntrl:] Matches control characters in ASCII range: 0x1-0x1F; 0x7

DIGIT

[:digit:] Matches digits in range of 0-9

GRAPH

[:graph:] Matches visible characters in the ASCII code range 0x21 - 0x7E

LOWER

[:lower:] Matches lowercase letters a-z

PRINT

[:print:] Matches printable characters in the ASCII code range 0x20 - 0x7E

PUNCT

[:punct:] Matches punctuation and symbols !"#$%&'()*+,\-./:;<=>?@[]^_`{|}~|

SPACE

[:space:] Matches all whitespace characters. In ASCII codes: 0x20; 0x9; 0xA 0xB; 0xC; 0xD

NSPACE

[!:space:] Matches all characters except whitespace.

UPPER

[:upper:] Matches uppercase letters A-Z

XDIGIT

[:xdigit:] Matches digits in hexadecimal notation 0x0 - 0xF

ASCII

[:ascii:] Matches all ASCII characters in the range of 0x0 - 0x7F

WORD

[:word:] Matches words: letters a-z; A-Z; numbers 0-9 and underscore _

[:any:]

Matches any character in ASCII range 0x0 - 0xff

Example

Extracting username field, which is expected to consist of only lowercase letters a to z, with minimum length of 4 characters and a maximum length of 15 characters:

plaintextcopydownload
2016-01-03 00:13:28,110.188.4.216,forerequest,200
2016-01-06 06:35:24,48.242.116.66,02rioting,200
2016-01-05 11:49:01,223.11.158.94,ribassano,404

plaintextcopydownload
TIMESTAMP:date_time  ','
IPADDR:ip            ','
LOWER{4,15}:username ','
LD EOL;

where:

1. extracts time and date, followed by field separator ','
2. extracts ip-address, followed by field separator ','
3. extracts username by matching lowercase characters, min 4, max 10 times, followed by field separator ','
4. matches but does not extract any character for the rest of the line

Results in first and third lines parsed into fields date_time, ip, username. The second line fails to parse because of username contains numbers.