All it required from me was to intentionally and manually type it down by hand instead of copy-pasting, on two purposeful occasions (within two minutes). Since then it's successfully saved in my brain.
echo "foo bar" | jq -Rr 'split(" ")[0]' # prints foo
$ echo -e "10:20: hello\n20:39: world" | jq -cR 'capture("^(?<timestamp>.*): (?<message>.*)$")'
{"timestamp":"10:20","message":"hello"}
{"timestamp":"20:39","message":"world"}
$ echo -e "10:20: hello\n20:39: world" | jq -Rn '[inputs | capture("(?<t>.*): (?<m>.*)$").m] | join(" ")'
"hello world"
for selecting the second column, PID, from `ps aux`,
ps aux | awk '{print $2}'
ps aux | jq -Rr 'split(" ")[1]'
ps aux | jq -Rr 'split("\\s+"; null)[1]'
E.g. for the `ps aux` example, using PowerShell, selecting a certain column:
gps | select id
The canonical shell tool to split fields is cut. Easy to use, simple to read.
For the very common use case to set variables to fields, use the shell built-in read. It uses the same IFS as the rest of the shell.
The main reason for this is that it's easy to add a grep-like step there, without invoking another tool. So I can add a range-test, a literal-test, or something more complex than I could do with grep.
In short I can go from:
awk '{ print $2 }'
awk '$1 == "en4:" {print $NF}'echo '999 888' | awk '{print $2}'
prints 888
echo '999 888' | cut -f2 -d " "
echo '999 888' | cut -f2 -d " " # notice two consecutive spaces
echo '999 888' | tr -s " " | cut -f2 -d " "