如何从Shell中的字符串中提取第一个字符？

Question

I have got a string (delimited by comma) from which I need to extract 'first character'

Eg  'A - one,B - two,C - three'

Expected output

A,B,C

Answer 1

echo 'A - one,B - two,C - three' | awk -F ',' '{OFS = ","} {for(i=1;i<=NF; i++) {$i=substr($i,1,1) }; print $0}'

Answer 2

For most cases, this should work (ascii)

echo 'A - one,B - two,C - three' | tr ',' '\n' | cut -b1

For character based selection (eg utf) this one is more suited

echo 'A - one,B - two,C - three' | tr ',' '\n' | cut -c1

Answer 3

sed解决方案：

echo 'A - one,B - two,C - three' | sed 's/\(.\)[^,]*,\{0,1\}/\1,/g;s/,$//'

Answer 4

This sed one-liner should work for your example:

sed -r 's/\s-[^,]*//g

Test:

kent$  sed -r 's/\s-[^,]*//g'<<< 'A - one,B - two,C - three' 
A,B,C

If you love to solve it with awk :

awk -F'\\s*-[^,]*' -v OFS="" '{$1=$1}7'

will work:

kent$   awk -F'\\s*-[^,]*' -v OFS="" '{$1=$1}7' <<<'A - one,B - two,C - three' 
A,B,C

Answer 5

I propose the following solution in "pure" bash:

X='A - one,B - two,C - three'

IFS=',' read -ra A <<< "$X"
RES=''
for W in "${A[@]}" ; do
   RES+=",${W:0:1}"
done

echo ${RES:1}

Answer 6

echo 'A - one,B - two,C - three'| awk '{print $1substr($3,4)substr($5,4)}'

A,B,C