In awk, you can remove all blank spaces from a string or field using the gsub function.
For example, to remove all blank spaces from the first field of each record in a file:
awk '{gsub(/ /,"",$1); print}' file.txt
In this example, the gsub function replaces all occurrences of a space character (represented by / /) with an empty string (represented by "") in the first field ($1) of each record. The modified record is then printed.
You can also use the gsub function to remove all blank spaces from a string stored in a variable. For example:
awk 'BEGIN{string="Hello World"; gsub(/ /,"",string); print string}'
This will print HelloWorld to the console.