How to crete a TSV file using Bash that takes as input some shell variables? - bash

Question

I have some shell variables which equal different types of values :
variable 1: 72.9%
variable 2: 27.1%
variable 3: Y
variable 4: 8756
I want to be able to print the values of these variables to a tab separated file and possibly even have the name of the variables as column headers
output:
variable1 variable2 variable3 variable4
72.9% 27.1% Y 8756
Any ideas?

Answer 1

Relatively easy, you just need to read the values one line-at-a-time into individual array variables and then provide the formatted output, e.g.
#!/bin/bash
declare -a name
declare -a num
declare -a value
while read -r a b c; do
name+=( "$a" )
num+=( "$b" )
value+=( "$c" )
done < "$1"
## C-style loop used to index both name & num for headings
for ((i = 0; i < ${#name[#]}; i++)); do
printf "%s\t" "${name[i]}${num[i]%:}"
done
echo
for i in "${value[#]}"; do
printf "%s\t\t" "$i"
done
echo
Which will result in tab separated headings and values (you may need to play with the spacing a bit -- e.g. using 2 tabs on value output)
Example Use/Output
$ bash headings.sh csvdata.txt
variable1 variable2 variable3 variable4
72.9% 27.1% Y 8756
If you have the variables in the script itself, you will have to take the same approach. With a variable, you have the name, but will need to create an array holding the names, as well as the values in order to loop over the values to provide the output you want. Whether you write a temp_file and read the values in, or use arrays to store the names of the variables (created by string concatenation between the number num above) the process will be the same.
Variables Already In Script
As mentioned above, you will take a similar approach, only here, you choose the heading prefix, and just use the loop counter to add the number at the end of whatever name you choose, then simply loop over the values you have stored in the array, e.g.
#!/bin/bash
foo="72.9%"
bar="27.1%"
baz="Y"
buz="8756"
declare -a value
value=( "$foo" "$bar" "$baz" "$buz" )
for ((i = 0; i < ${#value[#]}; i++)); do
printf "%s\t" "variable$((i+1))"
done
echo
for i in "${value[#]}"; do
printf "%s\t\t" "$i"
done
echo
Example Use/Output
(the same)
$ bash headings2.sh
variable1 variable2 variable3 variable4
72.9% 27.1% Y 8756