Commands by copremesis (11)

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Put a console clock in top right corner
Gives not only date but also some interesting status about the System

grep (or anything else) many files with multiprocessor power
Parallel does not suffer from the risk of mixing of output that xargs suffers from. -j+0 will run as many jobs in parallel as you have cores. With parallel you only need -0 (and -print0) if your filenames contain a '\n'. Parallel is from https://savannah.nongnu.org/projects/parallel/

Send apache log to syslog-ng
Send apache log to syslog-ng server without change configuration of syslog. Just add in httpd.conf or vhost conf.

find files ignoring .svn and its decendents
for when find . -print | grep -v .svn | xargs doesnt cut it.

Delete all but the latest 5 files
yes 6 (tail from 6th line)

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

Search through files, ignoring .svn

Clone or rescue a block device
If you use the logfile feature of ddrescue, the data is rescued very efficiently (only the needed blocks are read). Also you can interrupt the rescue at any time and resume it later at the same point. http://www.gnu.org/software/ddrescue/ddrescue.html

Mapreduce style processing
parallel can be installed on your central node and can be used to run a command multiple times. In this example, multiple ssh connections are used to run commands. (-j is the number of jobs to run at the same time). The result can then be piped to commands to perform the "reduce" stage. (sort then uniq in this example). This example assumes "keyless ssh login" has been set up between the central node and all machines in the cluster. bashreduce may also do what you want.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"


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