Tag Archive

aaomega amateur astronomy awk bash b[e] supergiant c-shell cartoon conference convert csh exoplanet fedora figaro fits fun galaxy history iraf jupiter latex linux lmc magellanic clouds massive star matplotlib meteor moon mypaper ondrejov observatory paper peblo photometry planet pyraf python scisoft skinakas observatory spectroscopy starlink talk theli ubuntu university of crete video wavelength

Log and awk

When using the log function of awk, then what we get as a result is the natural logarithmic of the input, like: …$ awk ‘BEGIN{print log(100)}’ …$ 4.60517 So in order to obtain the logarithm of base 10 (or any other base), we just need to divide the result with the logarithm of the base, […]

External variable inside awk

Sometimes, a variable may be needed to get inside awk (for or while loop for example). In order to pass the variable inside awk, include it like: awk -v i=$i ‘{ .. }’ test

Mean value and standard deviation of a column using awk

In order to get the mean value of column 1 (or any other) you type: $ awk ‘BEGIN{s=0;}{s=s+$1;}END{print s/NR;}’ file In order to get the standard deviation of column 1 you type: $ awk ‘{sum+=$1; sumsq+=$1*$1} END {print sqrt(sumsq/NR – (sum/NR)^2)}’ file or $ awk ‘{delta = $1 – avg; avg += delta / NR; […]