In /usr/bin/caca-config line 23:
  exit $1
       ^-- SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
  exit "$1"


In /usr/bin/caca-config line 36:
    -*=*) optarg=`echo "$1" | sed 's/[-_a-zA-Z0-9]*=//'` ;;
                 ^-- SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
    -*=*) optarg=$(echo "$1" | sed 's/[-_a-zA-Z0-9]*=//') ;;


In /usr/bin/caca-config line 94:
  echo $prefix
       ^-----^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
  echo "$prefix"


In /usr/bin/caca-config line 99:
  echo $exec_prefix
       ^----------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
  echo "$exec_prefix"


In /usr/bin/caca-config line 116:
  echo -L${prefix}/lib/x86_64-linux-gnu $libs
         ^-------^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
  echo -L"${prefix}"/lib/x86_64-linux-gnu $libs

For more information:
  https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...
  https://www.shellcheck.net/wiki/SC2006 -- Use $(...) notation instead of le...