mlr tac *.dat
mlr cut --complement -f os_version *.dat
mlr sort -f hostname,uptime *.dat

$ mlr --help
Usage: mlr [I/O options] {verb} [verb-dependent options ...] {file names}
Verbs:
   cat check count-distinct cut filter group-by group-like having-fields head
   histogram join label put regularize rename reorder sort stats1 stats2 step tac tail top
   uniq
Please use "mlr {verb name} --help" for verb-specific help.
Please use "mlr --help-all-verbs" for help on all verbs.

Functions for filter and put:
   abs acos acosh asin asinh atan atan2 atanh cbrt ceil cos cosh erf erfc exp
   expm1 floor invqnorm log log10 log1p max min pow qnorm round roundm sin sinh sqrt tan
   tanh urand + - - * / % ** == != > >= < <= && || ! strlen sub tolower toupper .
   boolean float int string hexfmt fmtnum gmt2sec sec2gmt systime
Please use "mlr --help-function {function name}" for function-specific help.
Please use "mlr --help-all-functions" or "mlr -f" for help on all functions.

Data-format options, for input, output, or both:
  --dkvp    --idkvp   --odkvp            Delimited key-value pairs, e.g "a=1,b=2" (default)
  --nidx    --inidx   --onidx            Implicitly-integer-indexed fields (Unix-toolkit style)
  --csv     --icsv    --ocsv             Comma-separated value (or tab-separated with --fs tab, etc.)
  --pprint  --ipprint --opprint --right  Pretty-printed tabular (produces no output until all input is in)
  --xtab    --ixtab   --oxtab            Pretty-printed vertical-tabular
  -p is a keystroke-saver for --nidx --fs space --repifs
Separator options, for input, output, or both:
  --rs      --irs     --ors              Record separators, defaulting to newline
  --fs      --ifs     --ofs    --repifs  Field  separators, defaulting to ","
  --ps      --ips     --ops              Pair   separators, defaulting to "="
  Notes (as of Miller v2.0.0):
  * RS/FS/PS are used for DKVP, NIDX, and CSVLITE formats where they must be single-character.
  * For CSV, PPRINT, and XTAB formats, RS/FS/PS command-line options are ignored.
  * DKVP, NIDX, CSVLITE, PPRINT, and XTAB formats are intended to handle platform-native text data.
    In particular, this means LF line-terminators on Linux/OSX.
  * CSV is intended to handle RFC-4180-compliant data.
    In particular, this means it *only* handles CRLF line-terminators.
  * This will change in v2.1.0, at which point there will be a (default-off) LF-termination option
    for CSV, multi-char RS/FS/PS, and double-quote support for DKVP.
Double-quoting for CSV:
  --quote-all                            Wrap all fields in double quotes
  --quote-none                           Do not wrap any fields in double quotes, even if they have OFS or ORS in them
  --quote-minimal                        Wrap fields in double quotes only if they have OFS or ORS in them
  --quote-numeric                        Wrap fields in double quotes only if they have numbers in them
Numerical formatting:
  --ofmt {format}                        E.g. %.18lf, %.0lf. Please use sprintf-style codes for double-precision.
                                         Applies to verbs which compute new values, e.g. put, stats1, stats2.
                                         See also the fmtnum function within mlr put (mlr --help-all-functions).
Other options:
  --seed {n} with n of the form 12345678 or 0xcafefeed. For put/filter urand().
Output of one verb may be chained as input to another using "then", e.g.
  mlr stats1 -a min,mean,max -f flag,u,v -g color then sort -f color
Please see http://johnkerl.org/miller/doc and/or http://github.com/johnkerl/miller for more information.
This is Miller version >= v2.0.0.

$ mlr sort --help
Usage: mlr sort {flags}
Flags:
  -f  {comma-separated field names}  Lexical ascending
  -n  {comma-separated field names}  Numerical ascending; nulls sort last
  -nf {comma-separated field names}  Numerical ascending; nulls sort last
  -r  {comma-separated field names}  Lexical descending
  -nr {comma-separated field names}  Numerical descending; nulls sort first
Sorts records primarily by the first specified field, secondarily by the second field, and so on.
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

--ofmt %.9le  --ofmt %.6lf  --ofmt %.0lf

$ echo 'x=3.1,y=4.3' | mlr put '$z=fmtnum($x*$y,"%08lf")'
x=3.1,y=4.3,z=13.330000

$ echo 'x=0xffff,y=0xff' | mlr put '$z=fmtnum(int($x*$y),"%08llx")'
x=0xffff,y=0xff,z=00feff01

$ echo 'x=0xffff,y=0xff' | mlr put '$z=hexfmt($x*$y)'
x=0xffff,y=0xff,z=0xfeff01

$ mlr check --help
Usage: mlr check
Consumes records without printing any output.
Useful for doing a well-formatted check on input data.

$ mlr count-distinct --help
Usage: mlr count-distinct [options]
-f {a,b,c}   Field names for distinct count.
Prints number of records having distinct values for specified field names. Same as uniq -c.

$ mlr count-distinct -f a,b then sort -nr count data/medium
a=zee,b=wye,count=455
a=pan,b=eks,count=429
a=pan,b=pan,count=427
a=wye,b=hat,count=426
a=hat,b=wye,count=423
a=pan,b=hat,count=417
a=eks,b=hat,count=417
a=eks,b=eks,count=413
a=pan,b=zee,count=413
a=zee,b=hat,count=409
a=eks,b=wye,count=407
a=zee,b=zee,count=403
a=pan,b=wye,count=395
a=wye,b=pan,count=392
a=zee,b=eks,count=391
a=zee,b=pan,count=389
a=hat,b=eks,count=389
a=wye,b=eks,count=386
a=hat,b=zee,count=385
a=wye,b=zee,count=385
a=hat,b=hat,count=381
a=wye,b=wye,count=377
a=eks,b=pan,count=371
a=hat,b=pan,count=363
a=eks,b=zee,count=357

$ mlr cut --help
Usage: mlr cut [options]
-f {a,b,c}       Field names to include for cut.
-o               Retain fields in the order specified here in the argument list.
                 Default is to retain them in the order found in the input data.
-x|--complement  Exclude, rather that include, field names specified by -f.
Passes through input records with specified fields included/excluded.

$ mlr filter --help
Usage: mlr filter [-v] {expression}
Prints records for which {expression} evaluates to true.
With -v, first prints the AST (abstract syntax tree) for the expression, which
gives full transparency on the precedence and associativity rules of Miller's grammar.
Please use a dollar sign for field names and double-quotes for string literals.
Miller built-in variables are NF NR FNR FILENUM FILENAME PI E.
Examples:
  mlr filter 'log10($count) > 4.0'
  mlr filter 'FNR == 2          (second record in each file)'
  mlr filter 'urand() < 0.001'  (subsampling)
  mlr filter '$color != "blue" && $value > 4.2'
  mlr filter '($x<.5 && $y<.5) || ($x>.5 && $y>.5)'
Please see http://johnkerl.org/miller/doc/reference.html for more information including function list.

$ mlr group-by --help
Usage: mlr group-by {comma-separated field names}
Outputs records in batches having identical values at specified field names.

$ mlr group-like --help
Usage: mlr group-like
Outputs records in batches having identical field names.

$ mlr having-fields --help
Usage: mlr having-fields [options]
--at-least  {a,b,c}
--which-are {a,b,c}
--at-most   {a,b,c}
Conditionally passes through records depending on each record's field names.

$ mlr head --help
Usage: mlr head [options]
-n {count}    Head count to print; default 10
-g {a,b,c}    Optional group-by-field names for head counts
Passes through the first n records, optionally by category.

$ mlr histogram --help
Usage: mlr histogram [options]
-f {a,b,c}    Value-field names for histogram counts
--lo {lo}     Histogram low value
--hi {hi}     Histogram high value
--nbins {n}   Number of histogram bins
Just a histogram. Input values < lo or > hi are not counted.

$ mlr --opprint put '$x2=$x**2;$x3=$x2*$x' then histogram -f x,x2,x3 --lo 0 --hi 1 --nbins 10 data/medium
bin_lo   bin_hi   x_count x2_count x3_count
0.000000 0.100000 1072    3231     4661
0.100000 0.200000 938     1254     1184
0.200000 0.300000 1037    988      845
0.300000 0.400000 988     832      676
0.400000 0.500000 950     774      576
0.500000 0.600000 1002    692      476
0.600000 0.700000 1007    591      438
0.700000 0.800000 1007    560      420
0.800000 0.900000 986     571      383
0.900000 1.000000 1013    507      341

$ mlr join --help
Usage: mlr join [options]
Joins records from specified left file name with records from all file names at the end of the Miller argument list.
Functionality is essentially the same as the system "join" command, but for record streams.
Options:
  -f {left file name}
  -j {a,b,c}   Comma-separated join-field names for output
  -l {a,b,c}   Comma-separated join-field names for left input file; defaults to -j values if omitted.
  -r {a,b,c}   Comma-separated join-field names for right input file(s); defaults to -j values if omitted.
  --lp {text}  Additional prefix for non-join output field names from the left file
  --rp {text}  Additional prefix for non-join output field names from the right file(s)
  --np         Do not emit paired records
  --ul         Emit unpaired records from the left file
  --ur         Emit unpaired records from the right file(s)
  -u           Enable unsorted input. In this case, the entire left file will be loaded into memory.
               Without -u, records must be sorted lexically by their join-field names, else not all
               records will be paired.
File-format options default to those for the right file names on the Miller argument list, but may be overridden
for the left file as follows. Please see the main "mlr --help" for more information on syntax for these arguments.
  -i {one of csv,dkvp,nidx,pprint,xtab}
  --irs {record-separator character}
  --ifs {field-separator character}
  --ips {pair-separator character}
  --repifs
  --repips
  --use-mmap
  --no-mmap
Please see http://johnkerl.org/miller/doc/reference.html for more information including examples.

$ mlr label --help
Usage: mlr label {new1,new2,new3,...}
Given n comma-separated names, renames the first n fields of each record to
have the respective name. (Fields past the nth are left with their original
names.) Particularly useful with --inidx, to give useful names to otherwise
integer-indexed fields.

$ mlr put --help
Usage: mlr put [-v] {expression}
Adds/updates specified field(s).
With -v, first prints the AST (abstract syntax tree) for the expression, which
gives full transparency on the precedence and associativity rules of Miller's grammar.
Please use a dollar sign for field names and double-quotes for string literals.
Miller built-in variables are NF NR FNR FILENUM FILENAME PI E.
Multiple assignments may be separated with a semicolon.
Examples:
  mlr put '$y = log10($x); $z = sqrt($y)'
  mlr put '$filename = FILENAME'
  mlr put '$colored_shape = $color . "_" . $shape'
  mlr put '$y = cos($theta); $z = atan2($y, $x)'
Please see http://johnkerl.org/miller/doc/reference.html for more information including function list.

$ mlr regularize --help
Usage: mlr regularize
For records seen earlier in the data stream with same field names in a different order,
outputs them with field names in the previously encountered order.
Example: input records a=1,c=2,b=3, then e=4,d=5, then c=7,a=6,b=8
output as              a=1,c=2,b=3, then e=4,d=5, then a=6,c=7,b=8

$ mlr rename --help
Usage: mlr rename {old1,new1,old2,new2,...}
Renames specified fields.

$ mlr reorder --help
Usage: mlr reorder [options]
-f {a,b,c}   Field names to reorder.
-e           Put specified field names at record end: default is to put at record start.
Example: mlr reorder    -f a,b sends input record "d=4,b=2,a=1,c=3" to "a=1,b=2,d=4,c=3".
Example: mlr reorder -e -f a,b sends input record "d=4,b=2,a=1,c=3" to "d=4,c=3,a=1,b=2".

$ mlr sort --help
Usage: mlr sort {flags}
Flags:
  -f  {comma-separated field names}  Lexical ascending
  -n  {comma-separated field names}  Numerical ascending; nulls sort last
  -nf {comma-separated field names}  Numerical ascending; nulls sort last
  -r  {comma-separated field names}  Lexical descending
  -nr {comma-separated field names}  Numerical descending; nulls sort first
Sorts records primarily by the first specified field, secondarily by the second field, and so on.
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

$ mlr --opprint sort -f a -nr x data/small
a   b   i x                   y
eks pan 2 0.7586799647899636  0.5221511083334797
eks wye 4 0.38139939387114097 0.13418874328430463
pan pan 1 0.3467901443380824  0.7268028627434533
wye pan 5 0.5732889198020006  0.8636244699032729
wye wye 3 0.20460330576630303 0.33831852551664776

$ head -n 10 data/multicountdown.dat
upsec=0.002,color=green,count=1203
upsec=0.083,color=red,count=3817
upsec=0.188,color=red,count=3801
upsec=0.395,color=blue,count=2697
upsec=0.526,color=purple,count=953
upsec=0.671,color=blue,count=2684
upsec=0.899,color=purple,count=926
upsec=0.912,color=red,count=3798
upsec=1.093,color=blue,count=2662
upsec=1.327,color=purple,count=917

$ head -n 20 data/multicountdown.dat | mlr --opprint sort -f color
upsec              color  count
0.395              blue   2697
0.671              blue   2684
1.093              blue   2662
2.064              blue   2659
2.2880000000000003 blue   2647
0.002              green  1203
1.407              green  1187
1.448              green  1177
2.313              green  1161
0.526              purple 953
0.899              purple 926
1.327              purple 917
1.703              purple 908
0.083              red    3817
0.188              red    3801
0.912              red    3798
1.416              red    3788
1.587              red    3782
1.601              red    3755
1.832              red    3717

$ mlr stats1 --help
Usage: mlr stats1 [options]
Options:
-a {sum,count,...}  Names of accumulators: p10 p25.2 p50 p98 p100 etc. and/or one or more of
                    count mode sum mean stddev var meaneb min max
-f {a,b,c}          Value-field names on which to compute statistics
-g {d,e,f}          Optional group-by-field names
Example: mlr stats1 -a min,p10,p50,p90,max -f value -g size,shape
Example: mlr stats1 -a count,mode -f size
Example: mlr stats1 -a count,mode -f size -g shape
Notes:
* p50 is a synonym for median.
* min and max output the same results as p0 and p100, respectively, but use less memory.
* count and mode allow text input; the rest require numeric input. In particular, 1 and 1.0
  are distinct text for count and mode.
* When there are mode ties, the first-encountered datum wins.

$ mlr stats2 --help
Usage: mlr stats2 [options]
-a {linreg-ols,corr,...}  Names of accumulators: one or more of
                          linreg-pca linreg-ols r2 corr cov covx
                          r2 is a quality metric for linreg-ols; linrec-pca outputs its own quality metric.
-f {a,b,c,d}              Value-field name-pairs on which to compute statistics.
                          There must be an even number of names.
-g {e,f,g}                Optional group-by-field names.
-v                        Print additional output for linreg-pca.
Example: mlr stats2 -a linreg-pca -f x,y
Example: mlr stats2 -a linreg-ols,r2 -f x,y -g size,shape
Example: mlr stats2 -a corr -f x,y

mlr filter '($x<.5 && $y<.5) || ($x>.5 && $y>.5)' data/medium > data/medium-squares

mlr --ofs newline stats2 -a linreg-pca -f x,y data/medium-squares
x_y_pca_m=1.014419
x_y_pca_b=0.000308
x_y_pca_quality=0.861354

# Set x_y_pca_m and x_y_pca_b as shell variables
eval $(mlr --ofs newline stats2 -a linreg-pca -f x,y data/medium-squares)

# In addition to x and y, make a new yfit which is the line fit. Plot using your favorite tool.
mlr --onidx put '$yfit='$x_y_pca_m'*$x+'$x_y_pca_b then cut -x -f a,b,i data/medium-squares \
  | pgr -p -title 'linreg-pca example' -xmin 0 -xmax 1 -ymin 0 -ymax 1

$ mlr step --help
Usage: mlr step [options]
-a {delta,rsum,...}   Names of steppers: one or more of
                      delta rsum counter
-f {a,b,c}            Value-field names on which to compute statistics
-g {d,e,f}            Group-by-field names
Computes values dependent on the previous record, optionally grouped by category.

$ each 10 uptime | mlr -p step -a delta -f 11
...
20:08 up 36 days, 10:38, 5 users, load averages: 1.42 1.62 1.73 0.000000
20:08 up 36 days, 10:38, 5 users, load averages: 1.55 1.64 1.74 0.020000
20:08 up 36 days, 10:38, 7 users, load averages: 1.58 1.65 1.74 0.010000
20:08 up 36 days, 10:38, 9 users, load averages: 1.78 1.69 1.76 0.040000
20:08 up 36 days, 10:39, 9 users, load averages: 2.12 1.76 1.78 0.070000
20:08 up 36 days, 10:39, 9 users, load averages: 2.51 1.85 1.81 0.090000
20:08 up 36 days, 10:39, 8 users, load averages: 2.79 1.92 1.83 0.070000
20:08 up 36 days, 10:39, 4 users, load averages: 2.64 1.90 1.83 -0.020000

$ mlr tac --help
Usage: mlr tac
Prints records in reverse order from the order in which they were encountered.

$ mlr tail --help
Usage: mlr tail [options]
-n {count}    Tail count to print; default 10
-g {a,b,c}    Optional group-by-field names for tail counts
Passes through the last n records, optionally by category.

$ mlr top --help
Usage: mlr top [options]
-f {a,b,c}    Value-field names for top counts
-g {d,e,f}    Optional group-by-field names for top counts
-n {count}    How many records to print per category; default 1
-a            Print all fields for top-value records; default is
              to print only value and group-by fields.
--min         Print top smallest values; default is top largest values
Prints the n records with smallest/largest values at specified fields, optionally by category.

$ mlr uniq --help
Usage: mlr uniq [options]
-g {d,e,f}    Group-by-field names for uniq counts
-c            Show repeat counts in addition to unique values
Prints distinct values for specified field names. With -c, same as count-distinct.

$ mlr --help-all-functions
abs        (math:       #args=1): Absolute value.
acos       (math:       #args=1): Inverse trigonometric cosine.
acosh      (math:       #args=1): Inverse hyperbolic cosine.
asin       (math:       #args=1): Inverse trigonometric sine.
asinh      (math:       #args=1): Inverse hyperbolic sine.
atan       (math:       #args=1): One-argument arctangent.
atan2      (math:       #args=2): Two-argument arctangent.
atanh      (math:       #args=1): Inverse hyperbolic tangent.
cbrt       (math:       #args=1): Cube root.
ceil       (math:       #args=1): Ceiling: nearest integer at or above.
cos        (math:       #args=1): Trigonometric cosine.
cosh       (math:       #args=1): Hyperbolic cosine.
erf        (math:       #args=1): Error function.
erfc       (math:       #args=1): Complementary error function.
exp        (math:       #args=1): Exponential function e**x.
expm1      (math:       #args=1): e**x - 1.
floor      (math:       #args=1): Floor: nearest integer at or below.
invqnorm   (math:       #args=1): Inverse of normal cumulative distribution function. Note that invqorm(urand()) is normally distributed.
log        (math:       #args=1): Natural (base-e) logarithm.
log10      (math:       #args=1): Base-10 logarithm.
log1p      (math:       #args=1): log(1-x).
max        (math:       #args=2): max of two numbers; null loses
min        (math:       #args=2): min of two numbers; null loses
pow        (math:       #args=2): Exponentiation; same as **.
qnorm      (math:       #args=1): Normal cumulative distribution function.
round      (math:       #args=1): Round to nearest integer.
roundm     (math:       #args=2): Round to nearest multiple of m: roundm($x,$m) is the same as round($x/$m)*$m
sin        (math:       #args=1): Trigonometric sine.
sinh       (math:       #args=1): Hyperbolic sine.
sqrt       (math:       #args=1): Square root.
tan        (math:       #args=1): Trigonometric tangent.
tanh       (math:       #args=1): Hyperbolic tangent.
urand      (math:       #args=0): Floating-point numbers on the unit interval. Int-valued example: '$n=floor(20+urand()*11)'.
+          (math:       #args=2): Addition.
-          (math:       #args=1): Unary minus.
-          (math:       #args=2): Subtraction.
*          (math:       #args=2): Multiplication.
/          (math:       #args=2): Division.
%          (math:       #args=2): Remainder; never negative-valued.
**         (math:       #args=2): Exponentiation; same as pow.
==         (boolean:    #args=2): String/numeric equality. Mixing number and string results in string compare.
!=         (boolean:    #args=2): String/numeric inequality. Mixing number and string results in string compare.
>          (boolean:    #args=2): String/numeric greater-than. Mixing number and string results in string compare.
>=         (boolean:    #args=2): String/numeric greater-than-or-equals. Mixing number and string results in string compare.
<          (boolean:    #args=2): String/numeric less-than. Mixing number and string results in string compare.
<=         (boolean:    #args=2): String/numeric less-than-or-equals. Mixing number and string results in string compare.
&&         (boolean:    #args=2): Logical AND.
||         (boolean:    #args=2): Logical OR.
!          (boolean:    #args=1): Logical negation.
strlen     (string:     #args=1): String length.
sub        (string:     #args=3): Example: '$name=sub($name, "old", "new")'. Regexes not supported.
tolower    (string:     #args=1): Convert string to lowercase.
toupper    (string:     #args=1): Convert string to uppercase.
.          (string:     #args=2): String concatenation.
boolean    (conversion: #args=1): Convert int/float/bool/string to boolean.
float      (conversion: #args=1): Convert int/float/bool/string to float.
int        (conversion: #args=1): Convert int/float/bool/string to int.
string     (conversion: #args=1): Convert int/float/bool/string to string.
hexfmt     (conversion: #args=1): Convert int to string, e.g. 255 to "0xff".
fmtnum     (conversion: #args=2): Convert int/float/bool to string using printf-style format string, e.g. "%06lld".
gmt2sec    (time:       #args=1): Parses GMT timestamp as integer seconds since epoch.
sec2gmt    (time:       #args=1): Formats seconds since epoch (integer part only) as GMT timestamp.
systime    (time:       #args=0): Floating-point seconds since the epoch.
To set the seed for urand, you may specify decimal or hexadecimal 32-bit
numbers of the form "mlr --seed 123456789" or "mlr --seed 0xcafefeed".
Miller's built-in variables are NF, NR, FNR, FILENUM, and FILENAME (awk-like)
along with the mathematical constants PI and E.