bash_tricks

21.9.2017

• miller plugin for bash

# convert a csv to a tabular format
mlr --icsv --opprint cat example.csv

# use cut to only show specific fields, call the field by typing the column name!
$ mlr --icsv --opprint cut -f columnname,shape example.csv

• whenever you want to parse out a section of a header, column name, etc... an effective method is to use sed to find and replace a part of the header with a tab then cut out the new field

sed -e 's/thingtocut/\t/' | cut -fx

# sed -e is for finding and replacing an expression
# \t is for tabular
# cut -fx -> x is for the field you would like to cut

• LC=all learn about this... it makes characters on your keyboard smaller bites of informationso that job run faster...

26.9.2017

• process subsitution allows for mulitple process to be inputed in another command, here is an example:

# before variable X and Y are joined, they are sorted by certain columns
# within each <() a process can take place before it is fed into another function
join -1 2 -2 4 -v2 <(sort -k2,2 $X) <(sort -k3,3 $Y)