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...