Freva – BUG – Basic User Guide (ALPHA VERSION)

November 14, 2016

1 Start the Evaluation System via Freva

... in the shell

To log in to the miklip system you may use ssh from any linux/unix system:

ssh -X

The -X will allow you to connect to the remote X server (e.g. to display images). user-account should be your account you usally login with, if you still don’t have one please ask the admins.

Start setting up the environment by loading the proper module (You may copy the following line as is into your shell):

module load freva

This activates the system for your current session. You might notice some other modules have been loaded.

... in the web

To log in to the research group system you may use a browser:

The domain could be different to the shell domain, depending on how the admins set up the system. Use your normal user account.

2 Work with the Evaluation System via Freva

Freva is the all in one framework with the main features: freva –help

Available commands:  
  --plugin       : Applies some analysis to the given data.  
  --history      : provides access to the configuration history (use --help for more help)  
  --databrowser  : Find data in the system  
  --crawl_my_data: Use this command to update your projectdata.  
  --esgf         : Browse ESGF data and create wget script  
This is the main tool for the evaluation system.  
Usage: freva --COMMAND [OPTIONS]  
To get help for the individual commands use  
  freva --COMMAND --help

The core applications are the plugin, history and databrowser — same in web and shell.

Example Table

Freva Option
–plugin apply some analysis tool freva –plugin pca outputdir=/tmp variable=tas
–history browse your history freva –history or freva –history –plugin movieplotter
–databrowser Search the research groups data freva –databrowser project=cmip5 variable=tas time_frequency=mon ensemble=r[1-5]i1p1 experiment=*196[0-5]
–crawl_my_data how2put your data into database freva –crawl_my_data –path=/PATH/2/USERDATA/user-account
–esgf Contact the esgf and retrieve the wget script freva –esgf –download-script /tmp/download.wget variable=tas time_frequency=mon ensemble=r1i1p1 experiment=decadal1965

All commands have a -h or -help flag to display the commands help. Basic commands for Freva:

To ...
To get the main help
freva –help
Click on Help
To list the plugins
freva –plugin
Click on Plugins
To list the plugin help
freva –plugin sometool –help
Click on a specific plugin
To see the history
freva –history
Click on History
To see the history help
freva –history –help
Read the buttons

2.1 Plugins –plugins

This is the main access to all installed analysis tools and the history. The tools are implemented by providing plug-ins to the system. For more information on how to create a plugin check the Basic Developer Guide (BDG).

Basic Usage

To get the help:

$ freva --plugin --help  
freva --plugin [opt] query  

To list all available analysis tools:

$ freva --plugin  
PCA: Principal Component Analysis  

The ”Overview” of tools in the framework.

To select a particular tool:

$ freva --plugin pca  
Missing required configuration for: input, variable

You see here that the PCA tool is complaining because of an incomplete configuration.

To get the help of a particular tool:

$ freva --plugin pca --help  
PCA (v3.1.0): Principal Component Analysis  
areaweight     (default: False)  
               Whether or not you want to have your data area weighted. This is  
               done per latitude with sqrt(cos(latitude)).  
boots          (default: 100)  
               Number of bootstraps.  
input          (default: None) [mandatory]  
               An arbitrary NetCDF file. There are only two restrictions to your  
               NetCDF file: a) Time has to be the very first dimension in the  
               variable you like to analyze. b) All dimensions in your variable  
               need to be defined as variables themselves with equal names.  
               Both, a) and b), are usually true.  

Here you see the configuration parameter, its default value (None means there is no value setup), whether the configuration is mandatory ([mandatory] marking by the default value) and an explanation about the configuration parameter.

To pass the values to the tool you just need to use the key=value construct like this:

$ freva --plugin pca outputdir=/tmp eofs=3  

You may even define variables in terms of other variables like the projection name above. While doing so from the shell please remember you need to escape the $ sign by using the backslash (
) or setting the value in single quotes (no, double quotes don’t work). For example:

$ freva --plugin pca input=myfile_\${eofs}.nc outputdir=/tmp eofs=3  
$ freva --plugin pca ’input=myfile_${eofs}.nc’ outputdir=/tmp eofs=3

If you want to know more about this bash feature see this and if you want to want to know much more then take a look at this

Quoting is very important on any shell, so if you use them, be sure to know how it works. It may help you avoid losing data!

Configuring the plugins

All configurations are saved in the –history can be seen, saved, return into a command and restarted!

You may want to save the configuration of the tool:

$ freva --plugin pca  
variable=tas outputdir=/tmp eofs=3  
INFO:__main__:Configuration file saved in  

Note this starts the tool. To just save the configuration without starting the tool use the -n or –dry-run flag. Also note this stores the configuration in a special directory structure so the system can find it again.

You can save the configuration somewhere else:

$ freva --plugin pca  
--dry-run --tool pca variable=tas outputdir=/tmp eofs=3  
INFO:__main__:Configuration file saved in pca.conf

The configuration stored will be used to overwrite the default one. This is a possible usecase:

Change the defaults to suit your general needs:

    $ freva --plugin pca --save-config=XXX --dry-run outputdir=/my_output_dir shiftlats=false

Prepare some configurations you’ll be using recurrently

    $ freva --plugin pca --save-config=XXX --dry-run  
     --config-file pca.tas.conf --tool pca variable=tas  
    $ freva --plugin pca --save-config=XXX --dry-run  
    --config-file pca.uas.conf --tool pca variable=uas


Instead of running your job directly in the terminal, you can involve the SLURM scheduler.

To run the tool murcss analyzing the variable tas the command is

$ freva --plugin murcss variable=tas ...

The execution takes a certain time (here: roughly 1 minute) and prints

Searching Files  
Remapping Files  
Calculating ensemble mean  
Calculating crossvalidated mean  
Calculating Anomalies  
Analyzing year 2 to 9  
Analyzing year 1 to 1  
Analyzing year 2 to 5  
Analyzing year 6 to 9  
Calculation took 63.4807469845 seconds

To schedule the same task you would use

$ freva --plugin murcss variable=tas ... --batchmode=true

instead. The output changes to

Scheduled job with history id 414  
You can view the job’s status with the command squeue  
Your job’s progress will be shown with the command  
tail -f  /home/zmaw/u290038/evaluation_system/slurm/murcss/slurm-1437.out

The last line shows you the command to view the output, which is created by the tool. In this example you would type

$ tail -f  /home/zmaw/u290038/evaluation_system/slurm/murcss/slurm-1437.out

For jobs with a long run-time or large amounts of jobs you schould consider to schedule them and use the batch mode!

$ freva --plugin --help  
Applies some analysis to the given data.  
See research group wiki for more information.  
The "query" part is a key=value list used for configuring the tool.  
It’s tool dependent so check that tool help.  
For Example:  
    freva --plugin pca eofs=4 bias=False outputdir=/tmp/test  
Usage: freva --plugin [options]  
  -d, --debug         turn on debugging info and show stack trace on  
  -h, --help          show this help message and exit  
  --repos-version     show the version number from the repository  
  --caption=CAPTION   sets a caption for the results  
  --save              saves the configuration locally for this user.  
  --save-config=FILE  saves the configuration at the given file path  
  --show-config       shows the resulting configuration (implies dry-run).  
  --scheduled-id=ID   Runs a scheduled job from database  
  --dry-run           dry-run, perform no computation. This is used for  
                      viewing and handling the configuration.  
  --batchmode=BOOL    creates a SLURM job

2.2 History –history

To get the history in the web just click on ’History’ and browse around. In the shell:

$ freva --history  
24) pca [2013-01-14 10:46:44.575529]  
<THIS MUST BE DEFINED!>.pca.<THIS MUST BE DEFINED!>.nc {u’normalize...  
23) pca [2013-01-14 10:46:01.322760] {u’normalize’: u’true’, u’testorthog’: u’true’, u’...  
22) nclplot [2013-01-11 14:51:40.910996]  
first_plot.eps {u’plot_name’: u’first_plot’, u’file_path’: u’tas_Am...  
21) nclplot [2013-01-11 14:44:15.297102]  
first_plot.eps {u’plot_name’: u’first_plot’, u’file_path’: u’tas_Am...  
20) nclplot [2013-01-11 14:43:37.748200]  
first_plot.eps {u’plot_name’: u’first_plot’, u’file_path’: u’tas_Am...  

It shows just the 10 latest entries, i.e. the 10 latest analysis that were performed. To create more complex queries check the help:

$ freva --history --help  
Displays the last 10 entries with a one-line compact description.  
The first number you see is the entry id, which you might  
use to select single entries.  
   Dates can be given in "YYYY-MM-DD HH:mm:ss.n" or any less accurate subset of it.  
   These are all valid: "2012-02-01 10:08:32.1233431", "2012-02-01 10:08:32",  
   "2012-02-01 10:08", "2012-02-01 10", "2012-02-01", "2012-02", "2012".  
   These are *NOT*: "01/01/2010", "10:34", "2012-20-01"  
   Missing values are assumed to be the minimal allowed value. For example:  
   "2012" == "2012-01-01 00:00:00.0"  
   Please note that in the shell you need to escape spaces.  
   All these are valid examples (at least for the bash shell):  
   freva --history --since=2012-10-1\ 10:35  
   freva --history --since=2012-10-1" "10:35’  
Usage: freva --history [options]  
  -d, --debug       turn on debugging info and show stack trace on exceptions.  
  -h, --help        show this help message and exit  
  --full_text       If present shows the complete configuration stored  
  --return_command  Show freva commands belonging to the history entries  
                    instead of the entries themself.  
  --limit=N         n is the number of entries to be displayed  
  --plugin=NAME     Display only entries from plugin "name"  
  --since=DATE      Retrieve entries older than date (see DATE FORMAT)  
  --until=DATE      Retrieve entries newer than date (see DATE FORMAT)  
  --entry_ids=IDs   Select entries whose ids are in "ids" (e.g. entry_ids=1,2  
                    or entry_ids=5)

You can view the configuration used at nay time and the satatus of the created files (i.e. if the files are still there or has been modified)

$ freva --history --plugin=pca --limit=1 --full_text  
26) pca v3.1.0 [2013-01-14 10:51:26.244553]  
  /home/user/evaluation_system/output/pca/ (deleted)

The history offers a more direct way to re-run tools. The option return_command shows the analyze command belonging to the configuration. Here an example for the tool movieplotter:

analyze --history --plugin=movieplotter --limit=1 --return_command

It returns:

freva --plugin movieplotter latlon=’None’ polar=’None’  
work=’/home/user/evaluation_system/cache/movieplotter/1387364295586’ reverse=’False’  
range_min=’None’ collage=’False’ range_max=’None’ earthball=’False’ level=’0’ ntasks=’24’  
/’’ loops=’0’  
colortable=’ncl_default’ animate=’True’ cacheclear=’True’ resolution=’800’  
outputdir=’/home/user/evaluation_system/output/movieplotter’ secperpic=’1.0’

This is not an handy expression, but very useful. A re-run of the tool in batch shell could be easily performed by

$(freva --history --plugin=movieplotter --limit=1 --return_command)

2.3 Data-Browser –databrowser

All files available on the MiKlip server are scanned and indexed in a special server (SOLR). This allows us to query the server which responds almost immediately. Because of the miklip configuration the first time you call the tool it might take up to a couple of seconds to start. After that normally you should see results within a second.

2.3.1 Help
freva --databrowser --help  
The query is of the form key=value. <value> might use *, ? as wildcards or any  
regular expression encclosed in forward slashes. Depending on your shell and  
the symbols used, remeber to escape the sequences properly.  
The safest would be to enclosed those in single quotes.  
For Example:  
    %s project=baseline1 model=MPI-ESM-LR experiment=/decadal200[0-3]/  
time_frequency=*hr variable=’/ta|tas|vu/’  
Usage: freva --databrowser [options]  
  -d, --debug           turn on debugging info and show stack trace on  
  -h, --help            show this help message and exit  
  --multiversion        select not only the latest version but all of them  
  --relevant-only       show only facets that filter results (i.e. >1 possible  
  --batch-size=N        Number of files to retrieve  
  --count-facet-values  Show the number of files for each values in each facet  
  --attributes          retrieve all possible attributes for the current  
                        search instead of the files  
  --all-facets          retrieve all facets (attributes & values) instead of  
                        the files  
  --facet=FACET         retrieve these facets (attributes & values) instead of  
                        the files

2.3.2 Usage

The databrowser expects a list of attribute=value (or key=value) pairs. There are a few differences and many more options (explained next).
Most important is that you don’t need to split the search according to the type of data you are searching for. You might as well search for files both on observations, reanalysis and model data all at the same time.

Also important is that all searches are made case insensitive (so don’t worry about upper or lower casing)

You can also search for attributes themselves instead of file paths. For example you can search for the list of variables available that satisfies a certain constraint (e.g. sampled 6hr, from a certain model, etc).

Defining the search

freva –databrowser project=baseline1 variable=tas time_frequency=mon

Defining the possible values

There are many more options for defining a value for a given attribute:

Attribute syntax  Meaning  
attribute=value  Search for files containing exactly that attribute  
attribute=val*  Search for files containing a value for attribute that  
starts with the prefix val  
attribute=*lue  Search for files containing a value for attribute that  
ends with the suffix lue  
attribute=*alu*  Search for files containing a value for attribute that  
has alu somewhere  
attribute=/.*alu.*/  Search for files containing a value for attribute that  
matches the given  
regular expression (yes! you might use any regular expression to find what you  
want. Check the table after this one)  
attribute=value1 attribute=value2  Search for files containing either  
value1 OR  
value2 for the given attribute (note that’s the same attribute twice!)  
attribute1=value1 attribute2=value2  Search for files containing value1 for  
AND value2 for attribute2  
attribute_not_=value  Search for files NOT containing value  
attribute_not_=value1 attribute_not_=value2  Search for files containing  
NEITHER value1 or value2

NOTE: When using * remember that your shell might give it a different meaning (normally it will try to match files with that name) to turn that off you can use backslash / in most shells

Regular Expressions must be given within forward slashes (/) and are match agains the whole value and not some part of it. Here’s a summary (there might be more... check it!) Syntax Meaning

<any_non_special_character>  that character  
Any one character  
[<any_character>]  Any one character between brackets  
[<any_character>-<any_other_character>]  Any one character between those characters  
(e.g. [a-e] is like [abcde]  
*  0 or more times  
+  1 or more times  
{n}  exactly n times  
{n,}  at least n times  
{n,m}  from n to m times  
RegExA|RegExB  Either RegExpA or RegExpB  
==Some examples==  
abc  exactly "abc"  
[abc]  either "a", "b" or "c"  
[abc]{3}  three characters from those given. E.g. "aaa", "bab" or "cab"  
[abc]{2,4}  two to four characters from those given. E.g. "aaa", "ab" or "cccc"  
[a-z]+[0-9]*  One ore more characters followed by cero or more number, e.g. "a",  
"tas", "cfaddbze94"

Searching for metadata

You might as well want to now about possible values that an attribute can take after a certain search is done. For this you use the –facet flag (facets are the possible attributes that partition the result set). For example to see the time frequency (time resolution) in which reanalysis are available you might issue the following query:

$ freva --databrowser --facet time_frequency project=reanalysis  
time_frequency: 6hr,day,mon

You might also ask for more than one single facet by definig the –facet flag multiple times. For example let’s also see a list of variables:

$ freva --databrowser --facet time_frequency --facet variable project=reanalysis  
variable: cl,clt,evspsbl,hfls,hfss,hur,hus,pr,prc,prsn,prw,ps,psl,rlds,rldscs,rlus,rlut,  
time_frequency: 6hr,day,mon

Please note that those are not related, i.e. the values of the time_frequency facet do not correspond to any particular variable. It is like issuing to difference queries.

Also note that you can further define this as usual with a given query. For example check which files are at 6hr frequency:

$ freva --databrowser --facet variable project=reanalysis time_frequency=6hr  
variable: psl,sfcwind,tas,zg

If you want to see how many files would return if you further select that variable (drill down query) you may add the –count-facet-values flag (simply –count will also do):

$ freva --databrowser --count-facet-values --facet variable project=reanalysis  
variable: psl (7991),sfcwind (33),tas (33),zg (131)

This means that there are 7991 files containing the variable psl, 33 for sfcwind, and so on.

If you want to check all facets at once you may use the –all-facets flag (don’t worry this is still very fast)

$ freva --databrowser --all-facets project=reanalysis  
time_frequency=6hrcmor_table: 6hrplev  
realm: atmos  
data_type: reanalysis  
institute: ecmwf,jma-criepi,nasa-gmao,ncep-ncar,noaa-cires  
time_frequency: 6hr  
experiment: 20cr,cfsr,eraint,jra-25,merra,merra_testarea,ncep1,ncep2  
variable: psl,sfcwind,tas,zg  
model: cdas,cfs,geos-5,ifs,jcdas,nomads  

And again you can also have the –count flag:

$ freva --databrowser --all-facets --count project=reanalysis time_frequency=6hr  
cmor_table: 6hrplev (8188)  
realm: atmos (8188)  
data_type: reanalysis (8188)  
institute: ecmwf (132),jma-criepi (66),nasa-gmao (99),ncep-ncar (163),noaa-cires (7728)  
time_frequency: 6hr (8188)  
experiment: 20cr (7728),cfsr (64),eraint (132),jra-25 (66),merra (66),  
merra_testarea (33),ncep1 (65),ncep2 (34)variable: psl (7991),sfcwind (33),  
tas (33),zg (131)model: cdas (99),cfs (64),geos-5 (99),ifs (132),jcdas (66),  
nomads (7728)  
ensemble: r10i1p1 (138),r11i1p1 (138),r12i1p1 (138),r13i1p1 (138),r14i1p1 (138),r15i1p1  
(138),r16i1p1 (138),r17i1p1 (138),r18i1p1 (138),r19i1p1 (138),r1i1p1 (598),r20i1p1 (138),  
r21i1p1 (138),r22i1p1 (138),r23i1p1 (138),r24i1p1 (138),r25i1p1 (138),r26i1p1 (138),  
r27i1p1 (138),r28i1p1 (138),r29i1p1 (138),r2i1p1 (138),r30i1p1 (138),r31i1p1 (138),  
r32i1p1 (138),r33i1p1 (138),r34i1p1 (138),r35i1p1 (138),r36i1p1 (138),r37i1p1 (138),  
r38i1p1 (138),r39i1p1 (138),r3i1p1 (138),r40i1p1 (138),r41i1p1 (138),r42i1p1 (138),  
r43i1p1 (138),r44i1p1 (138),r45i1p1 (138),r46i1p1 (138),r47i1p1 (138),r48i1p1 (138),  
r49i1p1 (138),r4i1p1 (138),r50i1p1 (138),r51i1p1 (138),r52i1p1 (138),r53i1p1 (138),  
r54i1p1 (138),r55i1p1 (138),r56i1p1 (138),r5i1p1 (138),r6i1p1 (138),r7i1p1 (138),  
r8i1p1 (138),r9i1p1 (138)

You might have also seen that some facets are not relevant at all as they are not partitioning the resulting data (e.g. see cmor_table or data_type). You can leave them out by adding the –relevant-only flag

$ freva --databrowser --all-facets --count --relevant-only project=reanalysis  
institute: ecmwf (132),jma-criepi (66),nasa-gmao (99),ncep-ncar (163),noaa-cires (7728)  
experiment: 20cr (7728),cfsr (64),eraint (132),jra-25 (66),merra (66),  
merra_testarea (33),ncep1 (65),ncep2 (34)  
variable: psl (7991),sfcwind (33),tas (33),zg (131)  
model: cdas (99),cfs (64),geos-5 (99),ifs (132),jcdas (66),nomads (7728)  
ensemble: r10i1p1 (138),r11i1p1 (138),r12i1p1 (138),r13i1p1 (138),  
r14i1p1 (138),r15i1p1 (138),r16i1p1 (138),r17i1p1 (138),r18i1p1 (138),  
r19i1p1 (138),r1i1p1 (598),r20i1p1 (138),r21i1p1 (138),r22i1p1 (138),  
r23i1p1 (138),r24i1p1 (138),r25i1p1 (138),r26i1p1 (138),r27i1p1 (138),  
r28i1p1 (138),r29i1p1 (138),r2i1p1 (138),r30i1p1 (138),r31i1p1 (138),  
r32i1p1 (138),r33i1p1 (138),r34i1p1 (138),r35i1p1 (138),r36i1p1 (138),  
r37i1p1 (138),r38i1p1 (138),r39i1p1 (138),r3i1p1 (138),r40i1p1 (138),  
r41i1p1 (138),r42i1p1 (138),r43i1p1 (138),r44i1p1 (138),r45i1p1 (138),  
r46i1p1 (138),r47i1p1 (138),r48i1p1 (138),r49i1p1 (138),r4i1p1 (138),  
r50i1p1 (138),r51i1p1 (138),r52i1p1 (138),r53i1p1 (138),r54i1p1 (138),  
r55i1p1 (138),r56i1p1 (138),r5i1p1 (138),r6i1p1 (138),r7i1p1 (138),  
r8i1p1 (138),r9i1p1 (138)

If you try to retrieve all variables stored (remember there are over +2.100.000 files!) you’ll notice an ellipses (...) ath the end of the list:

$ freva --databrowser --facet variable  
variable: abs550aer,ageice,agessc,albisccp,arag,areacella,areacello,bacc,baresoilfrac,  

This means there are more results than those being shown here. We limit the results to 100 for usability sake. If you still think this is a bug instead of a terrific feature, then you might use a special search word to change this facet.limit. That’s the number of results that will be retrieved. Setting it to -1 retrieves just everything... be aware that make cause some problems if you don’t know what you are doing (well sometimes it might also cause problems if you do... so use with discretion)

$ freva --databrowser --facet variable facet.limit=-1  

By the way, do you want to count them? Those are 619 variables!

$ freva --databrowser --facet variable facet.limit=-1 | tr ’,’ ’\n’ | wc -l  

Bash auto completion

And if that’s not awesome enough (I know it never is), then try the bash auto-completion. If you are using bash, everything is already setup when you issued the ’module load freva’ command. Whenever you hit tab the word will be completed to the longest unique string that matches your previous input. A second tab will bring up a list of all possible completions after that.

For example (?TAB? denotes presing the tab key):

freva --databrowser project=base<TAB>

results in

freva --databrowser project=baseline

Now pressing ?TAB? again will show all other possibilities:

$ freva --databrowser project=baseline<TAB>  
baseline0  baseline1

But flags are not the only thing being populated, it also work on atributes:

$ freva --databrowser <TAB><TAB>  
cmor_table=      ensemble=        institute=       project=         time_frequency=  
data_type=       experiment=      model=           realm=           variable=

... and of course values:

$ freva --databrowser institute=m<TAB><TAB>  
miroc  mohc   mpi-m  mri

And (yes! That wasn’t all) this is also query aware:

$ freva --databrowser institute=<TAB><TAB>  
bcc           csiro-bom     inpe          miroc         nasa-gsfc     nimr-kma  
bnu           csiro-qccce   ipsl          mohc          nasa-jpl      noaa-cires  
cccma         ecmwf         jma-criepi    mpi-m         nasa-larc     noaa-gfdl  
cmcc          fio           lasg-cess     mri           ncar          nsf-doe-ncar  
cnes          ichec         lasg-iap      nasa-giss     ncc           remss  
cnrm-cerfacs  inm           loa_ipsl      nasa-gmao     ncep-ncar

$ freva --databrowser project=reanalysis institute=<TAB><TAB>  
ecmwf       jma-criepi  nasa-gmao   ncep-ncar   noaa-cires

Note that if you mix flags this might not work as intended (or not at all).

2.4 –crawl_my_data

Per default it is loading the users ”projectdata” directory:

freva --crawl_my_data --help  
Use this command to update your projectdata.  
Usage: freva --crawl_my_data [options]  
  -d, --debug  turn on debugging info and show stack trace on exceptions.  
  -h, --help   show this help message and exit  
  --path=PATH  crawl the given directory

freva --crawl_my_data

would crawl all data you have in /research/database/data4project/projectdata/user-account

When you have a lot of data in your directory, it could be worth it, to take just a sub-directory. This gets much faster, when less data.

EXAMPLE: You’ve put in a new decadal experiment and just want to add this

freva --crawl_my_data --path  

2.5 –esgf

The search syntax is defined here:

It has been simplified to be used from the command line and resemble freva –databrowser as clos as possible. But the two commands rely on different backends which have different query possibilities.

The query is of the form key=value. the key might be repeated and/or negated with the  
’_not_’ suffix (e.g. model_not_=MPI-ESM-LR experiment=decadal2000 experiment=decadal2001)  
Simple query:  
    freva --esgf model=MPI-ESM-LR experiment=decadal2001 variable=tas distrib=False  
The search API is described here:  
Some special query keys:  
distrib: (*true*, false) search globally or only at DKRZ (MPI data and replicas)  
latest : (true, false, *unset*) search for the latest version, older ones or all.  
replica: (true, false, *unset*) search only for replicas, non-replicas, or all.  
Usage: freva --esgf [options]  
  -d, --debug           turn on debugging info and show stack trace on  
  -h, --help            show this help message and exit  
  --datasets            List the name of the datasets instead of showing the  
  --show-facet=FACET    <list> List all values for the given facet (might be  
                        defined multiple times). The results show the possible  
                        values of the selected facet according to the given  
                        constraints and the number of *datasets* (not files)  
                        that selecting such value as a constraint will result  
                        (faceted search)  
  --opendap             List the name of the datasets instead of showing the  
  --gridftp             Show Opendap endpoints instead of the http default  
                        ones (or skip them if none found)  
                        <file> Download wget_script for getting the files  
                        instead of displaying anything (only http)  
  --query=QUERY         <list> Display results from <list> queried fields


If you need some files: first check if they are there and how many they are:

$ freva --esgf project=CMIP5 experiment=decadal{1960..1965} variable=tas distrib=false latest=true | wc -l  

You can check those urls by just not piping the result to wc (word count)

$ freva --esgf project=CMIP5 experiment=decadal{1960..1965} variable=tas distrib=false latest=true  

And you can get the wget script, a bash script written around wget to simplify data download using this:

$ freva --esgf --download-script /tmp/scrip.wget  project=CMIP5 experiment=decadal{1960..1965} variable=tas distrib=false latest=true  
Download script successfully saved to /tmp/scrip.wget

By the way, the search looked for all files stored locally at DKRZ (distrib=false) holding the latest version (latest=true) of the variable tas (variable=tas) for the experiments decadal1960 to decadal1965 (this is a bash construct and not part of the search api!)