Center for Computational Molecular Science and Technology Georgia Institute of Technology Center for Computational Molecular Science and Technology School of Chemistry and Biochemistry

CCMST Weekly News, November 19 2010

November 19, 2010 12:37 pm EST

1. Announcements
2. Statistics
3. Tip of the Week

ANNOUNCEMENTS

Physical chemistry Division Seminar

November 30, 2010 4:00 PM – 5:00 PM
MoSE 3201A
Prof. John Kelly, Trinity College, Dublin

STATISTICS

FGATE

Uptime: 100 days
/home directory usage: 76% (1.4 TB available)
/backups directory usage: 100%

LSF usage for Week 45 (11/8-11/14) (times are in minutes)
GroupJobsTotal CPUAvg CPUAvg WaitAv g Trnr.
Bredas 209 265691 14% 1271 4154 5526
Hernandez 3643 263417 14% 72 280 372
Sherrill 381 212844 11% 559 3977 4515
Other 2 39746 2% 19873 0 18418
Total 4235 781696 40% 185 803 1007

Note: percentages refer to the total CPU time available for the period.

Most productive user of the Week: pwinget 187878.

EGATE

Uptime: 24 days
/theoryfs/common directory usage: 37% (424GB available)
/theoryfs/ccmst directory usage: 86% (126 GB available)

LSF usage for Week 45 (11/8-11/14) (times are in minutes)
GroupJobsTotal CPUAvg CPUAvg WaitAvg Trnr.
Hernandez 119 306 0% 3 0 50
Sherrill 1755 824477 55% 470 565 1039
Other 305 288031 19% 944 358 1314
Total 2179 1112814 74% 511 505 1023

Note: percentages refer to the total CPU time available for the period.

Most productive user of the Week: loriab 662892.

TIP OF THE WEEK

By Massimo

Unix I/O Redirection

The I/O redirection is a fundamental concept in Unix, and it is central for a productive use of a UNIX environment. In UNIX/Linux every program that is started by a shell has three open files associated to it by default:

  • Standard input, or STDIN, associated to channel 0.
  • Standard output, or STDOUT, associated to channel 1
  • Standard error, or STDERR, associated to channel 2

The UNIX I/O redirection operators, "<" and  ">" operate on STDIN and STDOUT, respectively. Here are some examples:

  • some-program < infile will assign the file infile as input of some-command.
  • some-program > outfile will assign the file outfile as output of some-command.
  • some-program < infile > outfile will redirect both input and output.

Other redirection operators are ">>" and "<<". The first is used to append the output of a command to the specified file, thus without overwriting the existing contents of the file. The double input redirection operator, "<<", is used mostly in shell scripts:

some-command << END_OF_INPUT
line 1
line 2
...
last input line
END_OF_INPUT

this construct tells the system that the input of some-command is to be taken from the current file stream up to the first occurrence of a marker string (in the above case the marker string is "END_OF_INPUT")

The construct for redirecting STDERR and merging it with STDOUT is different for bash and tcsh:

  • bash: some-command > outfile 2>&1
  • tcsh: some-command >& outfile

Do you have usage tips that you want to share with the other CCMST users? Please send them to Massimo (massimo.malagoli@chemistry.gatech.edu) for inclusion in the Tip of the Week section.