Issue
I'am trying to get the first character of each string using regex and BASH_REMATCH in shell script.
My input text file contain :
config_text = STACK OVER FLOW
The strings STACK OVER FLOW must be uppercase like that.
My output should be something like this :
SOF
My code for now is :
var = config_text
values=$(grep $var test_file.txt | tr -s ' ' '\n' | cut -c 1)
if [[ $values =~ [=(.*)]]; then
echo $values
fi
As you can see I'am using tr and cut but I'am looking to replace them with only BASH_REMATCH because these two commands have been reported in many links as not functional on MacOs.
I tried something like this :
var = config_text
values=$(grep $var test_file.txt)
if [[ $values =~ [=(.*)(\b[a-zA-Z])]]; then
echo $values
fi
VALUES as I explained should be :
S O F
But it seems \b does not work on shell script. Anyone have an idea how to get my desired output with BASH_REMATCH ONLY. Thanks in advance for any help.
Solution
A generic BASH_REMATCH solution handling any number of words and any separator.
local input="STACK OVER FLOW" pattern='([[:upper:]]+)([^[:upper:]]*)' result=""
while [[ $input =~ $pattern ]]; do
result+="${BASH_REMATCH[1]::1}${BASH_REMATCH[2]}"
input="${input:${#BASH_REMATCH[0]}}"
done
echo "$result"
# Output: "S O F"
Answered By - Philippe Answer Checked By - Marie Seifert (WPSolving Admin)