The following post explains steps I took to install and enable mongoDB 3.2.1 as a service running under CentOS 7.

Install development tools and libraries, download mongoDB and compile source, and install the compiled binaries:

$ sudo yum group install "Development Tools"
$ sudo yum install scons
$ sudo yum install glibc-static
$ curl -O
$ tar zxvf mongodb-src-r3.2.1.tar.gz
$ cd mongodb-src-r3.2.1
$ scons --ssl all
$ sudo scons --prefix=/opt/mongo install

Set up a mongod account and relevant directories:

$ sudo groupadd --system mongod
$ sudo useradd --no-create-home --system --gid mongod --home-dir /var/lib/mongo --shell /sbin/nologin --comment 'mongod' mongod
$ sudo mkdir -p /var/lib/mongo
$ sudo chown -R mongod:mongod /var/lib/mongo
$ sudo chmod 0755 /var/lib/mongo/
$ sudo mkdir -p /var/{run,log}/mongodb/
$ sudo chown mongod:mongod /var/{run,log}/mongodb/
$ sudo chmod 0755 /var/{run,log}/mongodb/
$ sudo mkdir -p /data/db
$ sudo chown -R mongod:mongod /data/db
$ sudo chmod -R o+w /data/db

Copy over mongod.conf and mongod.service configuration files with modifications for our setup:

$ sudo cp rpm/mongod.conf /etc/mongod.conf
$ sudo cp rpm/mongod.service /lib/systemd/system/mongod.service
$ sudo sed -i -e 's\/usr/local/bin/mongod\/opt/mongo/bin/mongod\' /lib/systemd/system/mongod.service

Reload daemon templates, and start and enable the mongoDB service:

$ sudo systemctl --system daemon-reload
$ sudo systemctl start mongod.service
$ sudo systemctl enable mongod.service

Confirm that the service is running properly:

$ sudo systemctl status mongod.service
● mongod.service - High-performance, schema-free document-oriented database
   Loaded: loaded (/usr/lib/systemd/system/mongod.service; enabled; vendor preset: disabled)
   Active: active (running) since Wed 2016-01-27 14:33:39 PST; 9min ago
 Main PID: 116789 (mongod)
   CGroup: /system.slice/mongod.service
           └─116789 /opt/mongo/bin/mongod --quiet -f /etc/mongod.conf run

Jan 27 14:33:39 systemd[1]: Started High-performance, schema-free document-oriented database.
Jan 27 14:33:39 systemd[1]: Starting High-performance, schema-free document-oriented database...
Jan 27 14:33:39 mongod[116787]: about to fork child process, waiting until server is ready for connections.
Jan 27 14:33:39 mongod[116787]: forked process: 116789
Jan 27 14:33:39 mongod[116787]: child process started successfully, parent exiting

You can also check the file /var/run/mongodb/ for a valid process ID value. Sometimes it might be necessary to create the parent folder so that the PID can be created:

$ sudo mkdir /var/run/mongodb/

You could also check the mongoDB log for other errors:

$ tail /var/log/mongodb/mongod.log

If the mongod service is not active, double-check that folders are named correctly in configuration and service files, and that permissions and ownership are set correctly on those folders. If anything is not named and attributed correctly, then the service will likely not start and note something like the following error:

about to fork child process, waiting until server is ready for connections. forked process: 1234 ERROR: child process failed, exited with error number 1

I hope this helps others with setting up mongoDB under CentOS — good luck!

Our research lab is non-profit, but private GitHub repositories still cost money, so I have been playing with GitLab Community Edition to serve up some private Git repositories from a third-party host on the cheap.

Before using GitLab CE, I had set up a Git repository that, for whatever reason, would not allow users to cache credentials and would also not allow access via https (SSL). It was getting pretty frustrating to have to type in a long string of credentials on every commit, so setting up a proper Git server was one of the goals.

Installing and setting up the server is pretty painless. After installing all the necessary files and editing the server’s configuration file, I go into the GitLab web console and add myself as a user, and then add myself as a master of a test repository called test-repo.

When I try to clone this test repository via https, I get a Peer's Certificate issuer is not recognized error, which prevents cloning.

To debug this, Git uses the curl framework, which I put into verbose mode:


When cloning, I get a bit more detail about the certificate issuer error message:

$ git clone
Cloning into 'test-repo'...
* Couldn't find host in the .netrc file; using defaults
* About to connect() to port 9999 (#0)
* Trying ...
* Connection refused
* Trying ...
* Connected to ( port 9999 (#0)
* Initializing NSS with certpath: sql:/etc/pki/nssdb
* failed to load '/etc/pki/tls/certs/renew-dummy-cert' from CURLOPT_CAPATH
* failed to load '/etc/pki/tls/certs/Makefile' from CURLOPT_CAPATH
* failed to load '/etc/pki/tls/certs/localhost.crt' from CURLOPT_CAPATH
* failed to load '/etc/pki/tls/certs/make-dummy-cert' from CURLOPT_CAPATH
* CAfile: /etc/pki/tls/certs/ca-bundle.crt
CApath: /etc/pki/tls/certs
* Server certificate:
* subject: CN=*,OU=Domain Control Validated
* start date: Oct 10 19:14:52 2013 GMT
* expire date: Oct 10 19:14:52 2018 GMT
* common name: *
* issuer: CN=Go Daddy Secure Certificate Authority - G2,OU=,O=", Inc.",L=Scottsdale,ST=Arizona,C=US
* Peer's Certificate issuer is not recognized.
* Closing connection 0
fatal: unable to access '': Peer's Certificate issuer is not recognized.

Something is up with the certificate from Go Daddy. From some Googling around, it looks like nginx doesn’t like using intermediate certificates to validate server certificates.

To fix this, I concatenate my wildcard CRT certificate file with GoDaddy’s intermediate and root certificates, which are available from their certificate repository:

$ sudo su -
# cd /etc/gitlab/ssl
# wget
# wget
# cat gdig2.crt gdroot-g2.crt >

I then edit the GitLab configuration file to point its nginx certificate file setting to this combined file:

# GitLab Nginx #
## see:

# nginx['enable'] = true
# nginx['client_max_body_size'] = '250m'
# nginx['redirect_http_to_https'] = true
# nginx['redirect_http_to_https_port'] = 443
nginx['ssl_certificate'] = "/etc/gitlab/ssl/"

Once this is done, I then reconfigure and restart GitLab the usual way:

$ sudo gitlab-ctl reconfigure
$ sudo gitlab-ctl restart

After giving the server a few moments to crank up, I then clone the Git repository:

$ git clone
Password for '': ...

I can even cache credentials!

$ git config credential.helper store

Much nicer than the previous, non-web setup.

The newer versions of emacs include JavaScript and other user modes useful for modern app development:

$ git clone git://
$ sudo yum groupinstall "Development Tools"
$ wget
$ tar jxvf autoconf-2.68.tar.bz2
$ cd autoconf-2.68
$ ./configure; make; sudo make install
$ sudo yum install texinfo libXpm-devel giflib-devel libtiff-devel libotf-devel  
$ cd ../emacs
$ make bootstrap; sudo make install

This process can take upwards of 20-30 minutes.

With the git repo state as of 24 March 2015:

$ emacs --version
GNU Emacs
Copyright (C) 2015 Free Software Foundation, Inc.
You may redistribute copies of GNU Emacs
under the terms of the GNU General Public License.
For more information about these matters, see the file named COPYING.


Finishing touches are in place for my convert2bed tool (GitHub site).

This utility converts common genomics data formats (BAM, GFF, GTF, PSL, SAM, VCF, WIG) to lexicographically-sorted UCSC BED format. It offers two benefits over alternatives:

  • It runs about 3-10x as fast as bedtools *ToBed equivalents
  • It converts all input fields in as non-lossy a way as possible, to allow recovery of data to the original format

As an example, here we use convert2bed on a 14M-read, indexed BAM file to a sorted BED file (data are piped to /dev/null) on a 4 GB, dual-Core 2 (2.4 GHz) workstation running RHEL 6:

$ samtools view -c ../DS27127A_GTTTCG_L001.uniques.sorted.bam

Conversion is performed with default options (sorted BED as output, using BEDOPS sort-bed):

$ time ./convert2bed -i bam < ../DS27127A_GTTTCG_L001.uniques.sorted.bam > /dev/null
[bam_header_read] EOF marker is absent. The input is probably truncated.

real 3m5.508s
user 0m25.702s
sys 0m8.602s

Here is the same conversion, performed with bedtools v2.22 bamToBed and sortBed:

$ time ../bedtools2/bin/bamToBed -i ../DS27127A_GTTTCG_L001.uniques.sorted.bam | ../bedtools2/bin/sortBed -i stdin > /dev/null

real    28m22.057s
user    2m58.579s
sys     0m41.605s

The use of convert2bed for this file offers a 9.1x speed improvement. Other large BAM files show similar conversion speedups.

Further time reductions are conferred with use of bam2bedcluster and bam2starchcluster scripts (TBA) which make use of GNU Parallel or a Sun Grid Engine job scheduler, reducing conversion time even further by breaking conversion tasks down by chromosome.

When testing is complete, code will be wrapped into the upcoming BEDOPS v2.4.3 release. Source is now available via GitHub.

Google once again has moved the print dialog box settings around in its browser, making it purposefully difficult to set the default print option to use the native OS X software. It wouldn’t be a problem if Chrome didn’t mess up what I’m trying to print! Here is a command to issue from, which seems to fix this bug with v37:

defaults write DisablePrintPreview -boolean true

For Google Canary nightly builds (v40-ish?), the following seems to work:

defaults write DisablePrintPreview -boolean true

Maybe it’s time to look into Safari again…

This mistake has caught me before, but I always overlook it:

Say we have a bunch of text files each containing a column of non-negative numerical values that we want to log-transform (base-10):

for i in `ls *.txt`; do echo $i; awk '{system("calc \"log("$1" + 1)\" | sed -e \"s/^[\t~]*//\"");}' $i > $i.transformed; done

Slow, but it seems to work in a pinch.


Cartograms with d3   TopoJSON   Same Sex Marriage

Shawn Allen wrote a d3.js-based implementation of a 2D cartogram, which sizes US states in an area-proportional manner, where area is based on some interesting statistic, like population.

There has been a great deal of progress made in the last year in defending the rights of GLBT Americans to marry and have their partnership rights acknowledged, rights like visitation and estate planning, rights that straight couples take for granted when visiting their loved one in the hospital, or sharing their lives in the house they own, etc.

It’s easy enough to see a map of the 50 states colored by legal status, but people are not spread out evenly to live across all states. I wanted to see how the United States was progressing as a factor of population.

I forked Allen’s project (GitHub project source code available here) and I redid the color scheme, which takes the 50 states and the District of Columbia and shades them by their legal status, whether their laws defend or remove same-sex marriage rights (and associated protections).

Green states allow same-sex marriage, light-green states allow civil unions, orange allow marriage or civil unions (but rulings are currently held up on appeal), and red states that do not defend same-sex marriage rights, either by explicit law or constitutional amendment.

I based the color assignments initially on data from the Right to Marry site, up-to-date as of May 19th, 2014. But with Pennsylvania’s Gov. Corbett conceding defeat and vowing not to appeal the ruling, I added Pennsylvania to the list of pro-equality states.

In addition to seeing how fast things have changed, what is also interesting is that drawing by area quickly shows that over half the country — by 2010 US Census population counts, at least — now enjoys (or will soon enjoy, pending appeals) legal protections that were once denied to a minority of Americans.

For scientific work, I have used matrix2png to make a nice PNG image from a text-formatted matrix of data values. PNG looks great on the web, but it doesn’t translate well to making publication-quality figures.

My thought was to take matrix2png and — with the help of Haru (libharu) — turn it into matrix2pdf. Maybe I can get this going on Github.