Update and caveat: This answer has a troubled past in that I confidently claimed things that turned out not to be true. I believe it has value in its current form, but please help me eliminate other inaccuracies (or convince me that it should be deleted altogether). I’ve substantially revised – and mostly gutted – … Read more
The “ is called Command Substitution and is equivalent to $() (parenthesis), while you are using ${} (curly braces). So all of these expressions are equal and mean “interpret the command placed inside”: joulesFinal=`echo $joules2 \* $cpu | bc` joulesFinal=$(echo $joules2 \* $cpu | bc) # v v # ( instead of { v # … Read more
Bash history expansion is a very odd corner in the bash command line parser, and you are clearly running into an unexpected history expansion, which is explained below. However, any sort of history expansion in a script is unexpected, because normally history expansion is not enabled in scripts; not even scripts run with the source … Read more
Non-trailing newlines are not removed The newlines you are looking for are there, you just don’t see them, because you use echo without quoting the variable. Validation: $ a=$( df -H ) $ echo $a Filesystem Size Used Avail Use% Mounted on /dev/sda3 276G 50G 213G 19% / udev 2.1G 4.1k 2.1G 1% /dev tmpfs … Read more
To assign the output of a command to an array, you need to use a command substitution inside of an array assignment. For a general command command this looks like: arr=( $(command) ) In the example of the OP, this would read: arr=($(grep -n “search term” file.txt | sed ‘s/:.*//’)) The inner $() runs the … Read more