Bash scripting - how to concatenate the following strings?

In one go:

printf '%s%s\n' "$(grep -Pom1 'extended model.*\(\K\d+' <(cpuid))" \
                "$(grep -Pom1 'extended family.*\(\K\d+' <(cpuid))"

The above leverages process substitution (<()), and command substitution ($()).

• The two command substitutions are replaced with the STDOUT of the commands inside

• cpuid command is put inside process substitution, the STDOUT will be returned as a file descriptor, grep will do the necessary matching on it, we have used grep with PCRE (-P) to get only (-o) the desired portion, and -m1 will stop after first match to avoid repetition

• printf is used to get the output in desired format

Example:

$ printf '%s%s\n' "$(grep -Pom1 'extended model.*\(\K\d+' <(cpuid))" "$(grep -Pom1 'extended family.*\(\K\d+' <(cpuid))"
30

You can avoid the intermediate file by using a pipe, and you can avoid using both sed and awk by doing your matching and substitution in awk e.g.

/usr/bin/cpuid | 
  awk '/extended model/ {mod = substr($4,3)} /extended family/ {fam = substr($4,3)} 
  END {printf "%d%d\n", mod, fam}'

Without making assumptions and changing the nature of the sample, here is a drop in replacement that stores the output in a variable as requested:

CPUID=$(/usr/bin/cpuid)
a=$(echo "$CPUID" | grep 'extended model' | sed 's/0x//' | awk ' { print $4 } ')
a+=$(echo "$CPUID" | grep 'extended family' | sed 's/0x//' | awk ' { print $4 } ')

First line sets the variable CPUID to the output of /usr/bin/cpuid
I then set the variable a to be the output (echo) of the CPUID variable set in the line above (this is then piped to your provided commands).