BASH output column formatting - bash

Question

First time posting. HELLO WORLD. Working on my first script that just simply checks if a list of my websites are online and then returns the HTTP code and the amount of time it took to return that to another file on my desktop.
-- THIS SCRIPT WILL BE RUNNING ON MAC OSX --
I would like to amend my script so that it formats its output into 3 neat columns.
currently
#!/bin/bash
file="/Users/USER12/Desktop/url-list.txt"
printf "" > /Users/USER12/Desktop/url-results.txt
while read line
do
printf "$line" >> /Users/USER12/Desktop/url-results.txt
printf "\t\t\t\t" >> /Users/USER12/Desktop/url-results.txt
curl -o /dev/null --silent --head --write-out '%{http_code} %{time_total}' "$line" >> /Users/USER12/Desktop/url-results.txt
printf "\n" >> /Users/USER12/Desktop/url-results.txt
done <"$file"
which outputs in the following format
google.com 200 0.389
facebook.com 200 0.511
abnormallyLongDomain.com 200 0.786
but i would like to format into neat aligned columns for easy reading
DOMAIN_NAME HTTP_CODE RESPONSE_TIME
google.com 200 0.389
facebook.com 200 0.511
abnormallyLongDomain.com 200 0.486
Thanks for the help everyone!!

Answer 1

column is very nice. You are, however, already using printf which gives you fine control over the output format. Using printf's features also allows the code to be somewhat simplified:
#!/bin/bash
file="/Users/USER12/Desktop/url-list.txt"
log="/Users/USER12/Desktop/url-results.txt"
fmt="%-25s%-12s%-12s\n"
printf "$fmt" DOMAIN_NAME HTTP_CODE RESPONSE_TIME > "$log"
while read line
do
read code time < <(curl -o /dev/null --silent --head --write-out '%{http_code} %{time_total}' "$line")
printf "$fmt" "$line" "$code" "$time" >> "$log"
done <"$file"
With the above defined format, the output looks like:
DOMAIN_NAME HTTP_CODE RESPONSE_TIME
google.com 301 0.305
facebook.com 301 0.415
abnormallyLongDomain.com 000 0.000
You can fine-tune the output format, such as spacing or alignment, by changing the fmt variable in the script.
Further Refinements
The above code opens and closes the log file with each loop. This can be avoided as Charles Duffy suggests, simply by using exec to redirect stdout to the log file before the first printf statement:
#!/bin/bash
file="/Users/USER12/Desktop/url-list.txt"
exec >"/Users/USER12/Desktop/url-results.txt"
fmt="%-25s%-12s%-12s\n"
printf "$fmt" DOMAIN_NAME HTTP_CODE RESPONSE_TIME
while read line
do
read code time < <(curl -o /dev/null --silent --head --write-out '%{http_code} %{time_total}' "$line")
printf "$fmt" "$line" "$code" "$time"
done <"$file"
Alternatively, as Chepner suggests, the print statements can be grouped:
#!/bin/bash
file="/Users/USER12/Desktop/url-list.txt"
fmt="%-25s%-12s%-12s\n"
{
printf "$fmt" DOMAIN_NAME HTTP_CODE RESPONSE_TIME
while read line
do
read code time < <(curl -o /dev/null --silent --head --write-out '%{http_code} %{time_total}' "$line")
printf "$fmt" "$line" "$code" "$time"
done <"$file"
} >"/Users/USER12/Desktop/url-results.txt"
An advantage of grouping is that, after the group, stdout is automatically restored to its normal value.

Answer 2

Shortened a bit
#!/bin/bash
file="./url.txt"
fmt="%s\t%s\t%s\n"
( printf "$fmt" "DOMAIN_NAME" "HTTP_CODE" "RESPONSE_TIME"
while read -r line
do
printf "$fmt" "$line" $(curl -o /dev/null --silent --head --write-out '%{http_code} %{time_total}' "$line")
done <"$file" ) | column -t > ./out.txt
Don't need redirect every printf but you can enclose the part of your script into (...) and run it in an subshell a redirect it's output. Print every field separated with one tab and use the column command to format it nicely.
Anyway, usually is better don't put filenames (nor headers) into the script and reduce it to
#!/bin/bash
while read -r line
do
printf "%s\t%s\t%s\n" "$line" $(curl -o /dev/null --silent --head --write-out '%{http_code} %{time_total}' "$line")
done | column -t
and use it like:
myscript.sh < url-list.txt >result.txt
this allows you use your script in pipes, like:
something_produces_urls | myscript.sh | grep 200 > somewhere.txt