Regular expression to capture both integer and float in bash-CodePudding

Can anyone help to capture the both int and float vaules using reg expression

I have below reg exp which will capture only int values but need to modify this for foot value also

'^[[:space:]]*([[:digit:]] )[[:space:]]*([kmg])b?[[:space:]]*$'

This works if the value is eg 23 MB but failing for 23.789 MB.

'^[[:space:]]*([[:digit:].] )[[:space:]]*([kmg])b?[[:space:]]*$'

CodePudding user response：

You can use

^[[:space:]]*([0-9] ([.][0-9] )?)[[:space:]]*([kmgKMG][bB]?)[[:space:]]*$

Details:

^ - start of string
[[:space:]]* - zero or more whitespaces
([0-9] ([.][0-9] )?) - Group 1: one or more digits and then an optional Group 2 matching a . and then one or more digits
[[:space:]]* - zero or more whitespaces
([kmgKMG][bB]?) - Group 3: k, m, g, K, M or G and then an optional b or B
[[:space:]]* - zero or more whitespaces
$ - end of string.

CodePudding user response：

Assuming that the string containing your number is stored in variable vstring, the following should do:

if [[ $vstring =~  ([ -]?[[:digit:]] ([.][[:digit:]] )?) ]]
then
  number=${BASH_REMATCH[1]}
else
  echo No number in $vstring 1>&2
fi

This also assumes that a floating point has not exponential part.