In /usr/bin/espdiff line 47: recurse=1 ^-----^ SC2034: recurse appears unused. Verify use (or export if used externally). In /usr/bin/espdiff line 51: compare=1 ^-----^ SC2034: compare appears unused. Verify use (or export if used externally). In /usr/bin/espdiff line 68: if [ $? -ne 0 ] ^-- SC2181: Check exit code directly with e.g. 'if mycmd;', not indirectly with $?. In /usr/bin/espdiff line 78: delay=$(($delay * 2)) ^----^ SC2004: $/${} is unnecessary on arithmetic variables. In /usr/bin/espdiff line 81: read -t $delay -p 'Please concentrate... ' || echo ^--^ SC2162: read without -r will mangle backslashes. For more information: https://www.shellcheck.net/wiki/SC2034 -- compare appears unused. Verify us... https://www.shellcheck.net/wiki/SC2162 -- read without -r will mangle backs... https://www.shellcheck.net/wiki/SC2004 -- $/${} is unnecessary on arithmeti...