Quick links:
Flags
Verbs
Functions
Glossary
Release docs
Online help¶
Miller has several online help mechanisms built in.
Main help¶
The front door is mlr --help or its synonym mlr -h. This leads you to mlr help topics with its list of specific areas:
mlr --help
Usage: mlr [flags] {verb} [verb-dependent options ...] {zero or more file names}
If zero file names are provided, standard input is read, e.g.
mlr --csv sort -f shape example.csv
Output of one verb may be chained as input to another using "then", e.g.
mlr --csv stats1 -a min,mean,max -f quantity then sort -f color example.csv
Please see 'mlr help topics' for more information.
Please also see https://miller.readthedocs.io
mlr help topics
Type 'mlr help {topic}' for any of the following:
Essentials:
mlr help topics
mlr help basic-examples
mlr help file-formats
Flags:
mlr help flags
mlr help flag
mlr help list-separator-aliases
mlr help list-separator-regex-aliases
mlr help comments-in-data-flags
mlr help compressed-data-flags
mlr help csv/tsv-only-flags
mlr help file-format-flags
mlr help flatten-unflatten-flags
mlr help format-conversion-keystroke-saver-flags
mlr help json-only-flags
mlr help legacy-flags
mlr help miscellaneous-flags
mlr help output-colorization-flags
mlr help pprint-only-flags
mlr help profiling-flags
mlr help separator-flags
Verbs:
mlr help list-verbs
mlr help usage-verbs
mlr help verb
Functions:
mlr help list-functions
mlr help list-function-classes
mlr help list-functions-in-class
mlr help usage-functions
mlr help usage-functions-by-class
mlr help function
Keywords:
mlr help list-keywords
mlr help usage-keywords
mlr help keyword
Other:
mlr help auxents
mlr help terminals
mlr help mlrrc
mlr help output-colorization
mlr help type-arithmetic-info
Shorthands:
mlr -g = mlr help flags
mlr -l = mlr help list-verbs
mlr -L = mlr help usage-verbs
mlr -f = mlr help list-functions
mlr -F = mlr help usage-functions
mlr -k = mlr help list-keywords
mlr -K = mlr help usage-keywords
Lastly, 'mlr help ...' will search for your exact text '...' using the sources of
'mlr help flag', 'mlr help verb', 'mlr help function', and 'mlr help keyword'.
Use 'mlr help find ...' for approximate (substring) matches, e.g. 'mlr help find map'
for all things with "map" in their names.
If you know the name of the thing you're looking for, use mlr help:
mlr help map
map: declares a map-valued local variable in the current curly-braced scope.
Type-checking happens at assignment: 'map b = 0' is an error. map b = {} is
always OK. map b = a is OK or not depending on whether a is a map.
To search by substring, use mlr help find:
mlr help find gmt
sec2gmtdate
Usage: ../c/mlr sec2gmtdate {comma-separated list of field names}
Replaces a numeric field representing seconds since the epoch with the
corresponding GMT year-month-day timestamp; leaves non-numbers as-is.
This is nothing more than a keystroke-saver for the sec2gmtdate function:
../c/mlr sec2gmtdate time1,time2
is the same as
../c/mlr put '$time1=sec2gmtdate($time1);$time2=sec2gmtdate($time2)'
sec2gmt
Usage: mlr sec2gmt [options] {comma-separated list of field names}
Replaces a numeric field representing seconds since the epoch with the
corresponding GMT timestamp; leaves non-numbers as-is. This is nothing
more than a keystroke-saver for the sec2gmt function:
mlr sec2gmt time1,time2
is the same as
mlr put '$time1 = sec2gmt($time1); $time2 = sec2gmt($time2)'
Options:
-1 through -9: format the seconds using 1..9 decimal places, respectively.
--millis Input numbers are treated as milliseconds since the epoch.
--micros Input numbers are treated as microseconds since the epoch.
--nanos Input numbers are treated as nanoseconds since the epoch.
-h|--help Show this message.
gmt2localtime (class=time #args=1,2) Convert from a GMT-time string to a local-time string. Consulting $TZ unless second argument is supplied.
Examples:
gmt2localtime("1999-12-31T22:00:00Z") = "2000-01-01 00:00:00" with TZ="Asia/Istanbul"
gmt2localtime("1999-12-31T22:00:00Z", "Asia/Istanbul") = "2000-01-01 00:00:00"
gmt2nsec (class=time #args=1) Parses GMT timestamp as integer nanoseconds since the epoch.
Example:
gmt2nsec("2001-02-03T04:05:06Z") = 981173106000000000
gmt2sec (class=time #args=1) Parses GMT timestamp as integer seconds since the epoch.
Example:
gmt2sec("2001-02-03T04:05:06Z") = 981173106
localtime2gmt (class=time #args=1,2) Convert from a local-time string to a GMT-time string. Consults $TZ unless second argument is supplied.
Examples:
localtime2gmt("2000-01-01 00:00:00") = "1999-12-31T22:00:00Z" with TZ="Asia/Istanbul"
localtime2gmt("2000-01-01 00:00:00", "Asia/Istanbul") = "1999-12-31T22:00:00Z"
nsec2gmt (class=time #args=1,2) Formats integer nanoseconds since epoch as GMT timestamp. Leaves non-numbers as-is. With second integer argument n, includes n decimal places for the seconds part.
Examples:
nsec2gmt(1234567890000000000) = "2009-02-13T23:31:30Z"
nsec2gmt(1234567890123456789) = "2009-02-13T23:31:30Z"
nsec2gmt(1234567890123456789, 6) = "2009-02-13T23:31:30.123456Z"
nsec2gmtdate (class=time #args=1) Formats integer nanoseconds since epoch as GMT timestamp with year-month-date. Leaves non-numbers as-is.
Example:
sec2gmtdate(1440768801700000000) = "2015-08-28".
sec2gmt (class=time #args=1,2) Formats seconds since epoch as GMT timestamp. Leaves non-numbers as-is. With second integer argument n, includes n decimal places for the seconds part.
Examples:
sec2gmt(1234567890) = "2009-02-13T23:31:30Z"
sec2gmt(1234567890.123456) = "2009-02-13T23:31:30Z"
sec2gmt(1234567890.123456, 6) = "2009-02-13T23:31:30.123456Z"
sec2gmtdate (class=time #args=1) Formats seconds since epoch (integer part) as GMT timestamp with year-month-date. Leaves non-numbers as-is.
Example:
sec2gmtdate(1440768801.7) = "2015-08-28".
Etc.
Command-line flags¶
This is a command-line version of the List of command-line flags page.
See mlr help flags for a full listing.
Per-verb help¶
This is a command-line version of the List of verbs page.
Given the name of a verb (from mlr -l) you can invoke it with --help or -h -- or, use mlr help verb:
mlr cat --help
Usage: mlr cat [options]
Passes input records directly to output. Most useful for format conversion.
Options:
-n Prepend field "n" to each record with record-counter starting at 1.
-N {name} Prepend field {name} to each record with record-counter starting at 1.
-g {a,b,c} Optional group-by-field names for counters, e.g. a,b,c
--filename Prepend current filename to each record.
--filenum Prepend current filenum (1-up) to each record.
-h|--help Show this message.
mlr group-like -h
Usage: mlr group-like [options] Outputs records in batches having identical field names. Options: -h|--help Show this message.
mlr help verb sort
sort
Usage: mlr sort {flags}
Sorts records primarily by the first specified field, secondarily by the second
field, and so on. (Any records not having all specified sort keys will appear
at the end of the output, in the order they were encountered, regardless of the
specified sort order.) The sort is stable: records that compare equal will sort
in the order they were encountered in the input record stream.
Options:
-f {comma-separated field names} Lexical ascending
-r {comma-separated field names} Lexical descending
-c {comma-separated field names} Case-folded lexical ascending
-cr {comma-separated field names} Case-folded lexical descending
-n {comma-separated field names} Numerical ascending; nulls sort last
-nf {comma-separated field names} Same as -n
-nr {comma-separated field names} Numerical descending; nulls sort first
-t {comma-separated field names} Natural ascending
-tr|-rt {comma-separated field names} Natural descending
-h|--help Show this message.
Example:
mlr sort -f a,b -nr x,y,z
which is the same as:
mlr sort -f a -f b -nr x -nr y -nr z
Etc.
Per-function help¶
This is a command-line version of the DSL built-in functions page.
Given the name of a DSL function (from mlr -f) you can use mlr help function for details:
mlr help function append
append (class=collections #args=2) Appends second argument to end of first argument, which must be an array.
mlr help function split
Function "split" not found.
mlr help function splita
splita (class=conversion #args=2) Splits string into array with type inference. First argument is string to split; second is the separator to split on.
Example:
splita("3,4,5", ",") = [3,4,5]
Etc.
REPL help¶
You can use :h or :help inside the REPL:
$ mlr repl
Miller v6.0.0-dev REPL for darwin:amd64:go1.16.5
Docs: https://miller.readthedocs.io
Type ':h' or ':help' for on-line help; ':q' or ':quit' to quit.
[mlr] :h
Options:
:help intro
:help examples
:help repl-list
:help repl-details
:help prompt
:help function-names
:help function-details
:help {function name}, e.g. :help sec2gmt
:help {function name}, e.g. :help sec2gmt
[mlr]
Manual page¶
If you've gotten Miller from a package installer, you should have man mlr producing a traditional manual page.
If not, no worries -- the manual page is a concatenated listing of the same information also available by each of the topics in mlr help topics. See also the Manual page which is an online copy.