Shellcheck: Fix warnings

shellcheck --exclude=SC2128 *.sh

Author: einarjon

01.sh

@@ -1,7 +1,7 @@
 #! /usr/bin/env bash
 input=${1:-1.txt}
-A=($(sort -n $input));
-for a in ${A[@]}; do grep -wq $((2020-a)) $input && break; done
+A=($(sort -n "$input"));
+for a in "${A[@]}"; do grep -wq $((2020-a)) "$input" && break; done
 echo "1A: $((2020-a)) + $a = $(((2020-a)*a))"
-b=:; for a in ${A[@]};do for i in ${A[@]}; do grep -wq $((2020-a-i)) $input && b=break; $b ; done; $b; done
+b=:; for a in "${A[@]}";do for i in "${A[@]}"; do grep -wq $((2020-a-i)) "$input" && b=break; $b ; done; $b; done
 echo "1B: $((2020-a-i)) + $a + $i = $(((2020-a-i)*a*i))"

02.sh

@@ -1,8 +1,8 @@
 #! /usr/bin/env bash
 ans=0
 IFS=$'-:\ \n'
-while read m M b c; do x=${c//[^$b]}; [[ ${#x} -ge $m && ${#x} -le $M ]] && ((++ans)); done < ${1:-2.txt}
+while read -r m M b c; do x=${c//[^$b]}; (( ${#x} >= m && ${#x} <= M && ++ans)); done < "${1:-2.txt}"
 echo "2A: $ans"
 ans=0
-while read m M b c; do x=${c:m-1:1}; y=${c:M-1:1}; [[ $x != $y ]] && [[ $b == $x || $b == $y ]] && ((++ans)); done < ${1:-2.txt}
+while read -r m M b c; do x=${c:m-1:1}; y=${c:M-1:1}; (( x != y && ( b == x || b == y ) && ++ans)); done < "${1:-2.txt}"
 echo "2B: $ans"

03.sh

@@ -1,8 +1,8 @@
 #! /usr/bin/env bash
-A=($(< ${1:-3.txt})); l=${#A[0]}; k=0; j=3; total=1; x=""
-for i in ${A[@]}; do x+=${i:k:1}; ((k=(k+j)%l)); done; x=${x//\.}
+A=($(< "${1:-3.txt}")); l=${#A[0]}; k=0; j=3; total=1; x=""
+for i in "${A[@]}"; do x+=${i:k:1}; ((k=(k+j)%l)); done; x=${x//\.}
 echo "3A: ${#x}"
 idx2=$(seq 0 2 $((${#A[@]}-1)))
-for j in 1 3 5 7; do x=""; k=0; for i in ${A[@]}; do x+=${i:k:1}; ((k=(k+j)%l)); done; x=${x//\.}; total+="*${#x}"; done
-for j in 1; do x=""; k=0; for i in $idx2; do x+=${A[i]:k:1}; ((k=(k+j)%l)); done ; x=${x//\.}; total+="*${#x}"; done
+for j in 1 3 5 7; do x=""; k=0; for i in "${A[@]}"; do x+=${i:k:1}; ((k=(k+j)%l)); done; x=${x//\.}; total+="*${#x}"; done
+x=""; k=0; for i in $idx2; do x+=${A[i]:k:1}; ((k=(k+j)%l)); done ; x=${x//\.}; total+="*${#x}"
 echo "3B: ${total:2} = $((total))"

04.sh

@@ -1,7 +1,7 @@
 #! /usr/bin/env bash
 X='epEhbiH'; x=$X; ans=0
 IFS=$' \n'
-A=($(sed s/^$/XXX/ ${1:-4.txt}))
+A=($(sed s/^$/XXX/ "${1:-4.txt}"))
 for i in "${A[@]}" XXX; do
     case $i in
         ecl:*) x=${x/e};;

05.sh

@@ -1,4 +1,4 @@
 #! /usr/bin/env bash
-A=($(cat ${1:-5.txt} | tr 'FBLR' '0101' | sort -nr))
+A=($(tr 'FBLR' '0101' < "${1:-5.txt}" | sort -nr))
 echo "5A: $((2#$A))"
-j=; for i in ${A[@]}; do [[ ${j: -1} == ${i: -1} ]] && echo "5B: $((2#$j-1))=$((2#$i+1))"; j=$i; done
+j=; for i in "${A[@]}"; do [[ "${j: -1}" == "${i: -1}" ]] && echo "5B: $((2#$j-1))=$((2#$i+1))"; j=$i; done

06.sh

@@ -1,8 +1,8 @@
 #! /usr/bin/env bash
 X=abcdefghijklmnopqrstuvwxyz; x=$X; a=0
-A=($(sed s/^$/X/ ${1:-6.txt}))
+A=($(sed s/^$/X/ "${1:-6.txt}"))
 A+=(X)
-while read -n1 i; do
+while read -r -n1 i; do
     [ "$i" = X ] && { ((a+=26-${#x})); x=$X; }
     x=${x/$i}
 done <<< "${A[*]}"
@@ -13,8 +13,8 @@ for line in "${A[@]}"; do
   if [[ "$line" = X ]]; then ((a+=${#x})); x=X;
   elif [ "$x" = X ]; then x=$line;
   else
-      y=""; while read -n1 i; do [[ ${x/$i} != ${x} ]] && y+="$i"; done <<< $line
-    #  y="";for ((i=0;i<${#line};i++ )); do [[ ${x/${line:i:1}} != ${x} ]] && y+="${line:i:1}"; done
+      y=""; while read -r -n1 i; do [[ ${x/$i} != "${x}" ]] && y+="$i"; done <<< "$line"
+      #y="";for ((i=0;i<${#line};i++ )); do [[ ${x/${line:i:1}} != ${x} ]] && y+="${line:i:1}"; done
       x=$y;
   fi
 done

07.sh

@@ -1,19 +1,19 @@
 #! /usr/bin/env bash
 IFS=$'\n'
 input=${1:-7.txt}
-NEW=($(grep " shiny gold" $input))
+NEW=($(grep " shiny gold" "$input"))
 FOUND=("${NEW[@]// bag*}")
 BAGS=("${NEW[@]}")
 while [ ${#FOUND[@]} != 0 ]; do
-    NEW=($(grep -F "${FOUND[*]}" $input | grep -v -F "${BAGS[*]}" | sort -u))
+    NEW=($(grep -F "${FOUND[*]}" "$input" | grep -v -F "${BAGS[*]}" | sort -u))
     BAGS+=("${NEW[@]}")
     FOUND=("${NEW[@]// bag*}")
 done
 echo "7A: ${#BAGS[@]}"
 r(){
     local A=() a=${1// *} b=0 c=0
-    A=($(grep ^${1:2} $input | grep -o "[0-9] [a-z]* [a-z]*"))
-    for i in "${A[@]}"; do c=$(r $i); ((b+=c)); done
+    A=($(grep "^${1:2}" "$input" | grep -o "[0-9] [a-z]* [a-z]*"))
+    for i in "${A[@]}"; do c=$(r "$i"); ((b+=c)); done
     echo $((a+a*b))
 }
 total=$(r "1 shiny gold")

08.sh

@@ -1,6 +1,6 @@
 #! /usr/bin/env bash
 IFS=$'\n'
-A=($(< ${1:-8.txt}))
+A=($(< "${1:-8.txt}"))
 B=("${A[@]}")
 solve8() {
     acc=0; i=0;
@@ -19,7 +19,7 @@ solve8() {
 solve8 || echo "8A: $acc"
 
 A=("${B[@]}");
-for k in ${!A[@]}; do
+for k in "${!A[@]}"; do
     if   [ ${A[k]:0:3} = nop ]; then A[k]=${A[k]/nop/jmp};
     elif [ ${A[k]:0:3} = jmp ]; then A[k]=${A[k]/jmp/nop};
     else continue; fi

09.sh

@@ -1,25 +1,24 @@
 #! /usr/bin/env bash
-A=($(< ${1:-9.txt}))
+A=($(< "${1:-9.txt}"))
 idx=(${!A[@]})
-for i in ${idx[@]:25}; do
+for i in "${idx[@]:25}"; do
     b=:
-    for j in ${idx[@]:i-25:25-1}; do
-        [ ${A[j]} -ge ${A[i]} ] && continue
-        for k in ${idx[@]:j+1:i-j-1}; do
-            [[ $((${A[j]}+${A[k]})) == ${A[i]} ]] && b=break; $b
+    for j in "${idx[@]:i-25:25-1}"; do
+        [[ ${A[j]} -ge ${A[i]} ]] && continue
+        for k in "${idx[@]:j+1:i-j-1}"; do
+            ((A[j]+A[k] == A[i])) && b=break; $b
         done
         $b
     done
     [ "$b" = ":" ] && echo "9A: line $i = ${A[i]}" && break
 done
 
 k=0; j=0; sum=${A[j++]}
-while [ $sum != ${A[i]} ]; do
+while [ "$sum" != "${A[i]}" ]; do
     if   [[ $sum -lt ${A[i]} ]]; then ((sum+=A[j++]))
     elif [[ $sum -gt ${A[i]} ]]; then ((sum-=A[k++]))
     fi
     [[ $j -ge $i ]] && echo NOT FOUND && break
 done
-IFS=$'\n'
-B=($(echo "${A[*]:k:j-k+1}" | sort -n))
+B=($(printf "%s\n" "${A[*]:k:j-k+1}" | sort -n))
 echo "9B: $j..$k = $((B+B[${#B[@]}-1]))"

10.sh

@@ -1,10 +1,10 @@
 #! /usr/bin/env bash
-A=($(sort -n ${1:-10.txt}))
+A=($(sort -n "${1:-10.txt}"))
 DIFF=(0 0 0 1) # add 3 for the built-in
-j=0; for i in "${A[@]}"; do ((DIFF[i-j]+=1));j=$i; done
-echo "10A: ${DIFF[1]}*${DIFF[3]}=$((${DIFF[1]}*${DIFF[3]}))"
+j=0; for i in "${A[@]}"; do ((DIFF[i-j]+=1)); j=$i; done
+echo "10A: ${DIFF[1]}*${DIFF[3]}=$((DIFF[1]*DIFF[3]))"
 B=; j=0; for i in "${A[@]}"; do B+=$((i-j)); j=$i; done; B+=3;
 C=(${B//3/ }) # only works because there are nothing but 1s and 3s
 D=(0 1 2 4 7)
-total=1; for i in "${C[@]}"; do total+=*${D[${#i}]}; done
+total=1; for i in "${C[@]}"; do total+="*${D[${#i}]}"; done
 echo "10B: ${total:2} = $((total))"

11.sh

@@ -1,9 +1,9 @@
 #! /usr/bin/env bash
-A=($(tr "L" "X" < ${1:-11.txt}))
+A=($(tr "L" "X" < "${1:-11.txt}"))
 B=(.${A//?/.}.); for i in "${A[@]}"; do B+=(.$i.); done; B+=($B); C=("${B[@]}");
-J=$(seq 1 ${#A}); I=$(seq 1 ${#A[@]}); change=($I); round=0
+J=$(seq 1 ${#A}); I=$(seq 1 ${#A[@]}); CHANGE=($I); round=0
 while [ ${#change} != 0 ]; do
-    change=(); l=
+    CHANGE=(); l=
     for i in $I; do
         for j in $J; do
             x=${B[i]:j:1}
@@ -14,23 +14,23 @@ while [ ${#change} != 0 ]; do
             fi
             l+=$x
         done
-        [ "${B[i]}" != .$l. ] && change+=($((i-1)) $i $((i+1)))
+        [ "${B[i]}" != .$l. ] && CHANGE+=($((i-1)) $i $((i+1)))
         C[i]=.$l.; l=
     done
     B=("${C[@]}")
-    I=$(printf "%s\n" ${change[@]} |sort -u)
+    I=$(printf "%s\n" "${CHANGE[@]}" |sort -u)
     ((++round==1)) && B=("${C[@]//X/x}")
     #((round%10)) || echo "$round: $((${#change[@]}/3))"
 done
 ans="${B[*]}"; ans=${ans//[ L.]}
 echo "11A: ${#ans}"
 
-#A=($(< ${1:-11.txt}))
+#A=($(< "${1:-11.txt}"))
 B=(L${A//?/L}L); for i in "${A[@]}"; do B+=(L${i}L); done; B+=($B)
 J=$(seq ${#A}); I=$(seq ${#A[@]}); change=1; round=0
 while [ ${#change} != 0 ]; do
     change=""; C=($B); l=""
-    for i in $I; do
+    for i in $I; do # shellcheck disable=SC2034
         for j in $J; do
             x=${B[i]:j:1}
             [[ "$x" != "L" && "$x" != "X" ]] && l+=$x && continue
@@ -46,7 +46,7 @@ while [ ${#change} != 0 ]; do
             s=${s//L}
             if [[ ${#s} == 0 ]]; then l+=X; elif [[ ${#s} -ge 5 ]]; then l+=L; else l+=$x; fi
         done
-        [ ${B[i]} != L${l}L ] && change+=1
+        [ "${B[i]}" != "L${l}L" ] && change+=1
         C+=(L${l}L); l=
     done
     C+=($B); B=("${C[@]}")

12.sh

@@ -1,33 +1,33 @@
 #! /usr/bin/env bash
-A=($(< ${1:-12.txt}))
+A=($(< "${1:-12.txt}"))
 H=1; X=0; Y=0; D=(N E S W)
 for i in "${A[@]}"; do
     i=${i/F/${D[H]}}
     n=${i:1}
     case $i in
-        N*) ((Y+=n));;
-        S*) ((Y-=n));;
-        E*) ((X+=n));;
-        W*) ((X-=n));;
-        R*) ((H=((n/90)+H)%4));;
-        L*) ((H=((-n/90)+H)%4));;
-        *) echo ERROR $i; break;;
+        N*) Y+=+$n;;
+        S*) Y+=-$n;;
+        E*) X+=+$n;;
+        W*) X+=-$n;;
+        R*) H=$((((n/90)+H)%4));;
+        L*) H=$((((-n/90)+H)%4));;
+        *) echo "ERROR $i"; break;;
     esac
 done
-echo "12A: $X+$Y = $((${X/-}+${Y/-}))"
+echo "12A: $((X))+$((Y)) = $(((X<0?-X:X)+(Y<0?-Y:Y)))"
 H=1; X=10; Y=1; x=0; y=0
 for i in "${A[@]}"; do
     n=${i:1}
     case $i in
-        N*) ((Y+=n));;
-        S*) ((Y-=n));;
-        E*) ((X+=n));;
-        W*) ((X-=n));;
+        N*) Y+=+$n;;
+        S*) Y+=-$n;;
+        E*) X+=+$n;;
+        W*) X+=-$n;;
         F*) ((x+=n*X,y+=n*Y));;
         R90|L270)   TMP=$X; ((X=Y,Y=-TMP));;
         R270|L90)   TMP=$X; ((X=-Y,Y=TMP));;
         R180|L180)  ((X=-X,Y=-Y));;
-        *) echo ERROR $i; break;;
+        *) echo "ERROR $i"; break;;
     esac
 done
-echo "12B: $x+$y = $((${x/-}+${y/-}))"
+echo "12B: $x+$y = $(((x<0?-x:x)+(y<0?-y:y)))"

13.sh

@@ -1,20 +1,20 @@
 #! /usr/bin/env bash
 IFS=$',\n'
 input=${1:-13.txt}
-A=($(sed s/x,//g $input))
+A=($(sed s/x,//g "$input"))
 time=$A; min=($A 0)
 for i in "${A[@]:1}"; do
     w=$((i-time%i))
-    [ $w -lt $min ] && min=($w $i)
+    (( w < min )) && min=($w $i)
 done
-echo "13A: $min*${min[1]} = $((min*${min[1]}))"
+echo "13A: $min*${min[1]} = $((min[0]*min[1]))"
 
-A=($(tail -1 $input))
-for i in ${!A[@]}; do [ ${A[i]} != x ] && B[$i]=${A[i]} ; done
+A=($(tail -1 "$input"))
+for i in "${!A[@]}"; do [ "${A[i]}" != x ] && B[$i]=${A[i]} ; done
 N=0; step=1
 #echo "${!B[@]} => "${B[@]}""
 for i in "${!B[@]}"; do
-    while (((N+i)%${B[$i]})); do ((N+=step)); done
-    ((step*=${B[$i]}))
+    while (((N+i)%B[i])); do ((N+=step)); done
+    ((step*=B[i]))
 done
 echo "13B: $N"

14.sh

@@ -1,31 +1,32 @@
 #! /usr/bin/env bash
 IFS=$'\n'
-A=($(< ${1:-14.txt}))
+A=($(< "${1:-14.txt}"))
+declare -a mem
 for i in "${A[@]}"; do
     case $i in
         mask*) y=${i//*= }; o=$((2#${y//X/0})); z=$((2#${y//X/1}));;
-        mem*)  y=${i//*= }; eval ${i// =*}=$(((y&z)|o));;
+        mem*)  y=${i//*= }; eval "${i// =*}=$(((y&z)|o))";;
     esac
 done
-sum=$(echo ${mem[*]}| tr ' ' '+')
+printf -v sum "+%s" "${mem[@]}"
 echo "14A: $((sum))"
 
 r() {
     local x=${2/X/0}
     if [ "$x" = "$2" ]; then
         mem2[$1|(2#$x)]=$3
     else
-        r $1 $x $3
-        r $1 ${2/X/1} $3
+        r "$1" "$x" "$3"
+        r "$1" "${2/X/1}" "$3"
     fi
 }
 
 IFS=$' []=\n'
-while read i y _ v; do
+while read -r i y _ v; do
    case "$i" in
        mask*) o=$((2#${y//X/0})); m=${y//1/0}; z=$((~2#${m//X/1}));;
-       mem*)  r $(((y&z)|o)) $m $v;;
+       mem*)  r $(((y&z)|o)) "$m" "$v";;
    esac
-done < ${1:-14.txt}
-sum=$(echo ${mem2[*]}| tr ' ' '+')
+done < "${1:-14.txt}"
+printf -v sum "+%s" "${mem2[@]}"
 echo "14B: $((sum))"

15.sh

@@ -1,9 +1,9 @@
 #! /usr/bin/env bash
-A=($(<${1:-15.txt}))
+A=($(<"${1:-15.txt}"))
 GIVEUP=${2:-10}
 #A=(0 3 6)
 B=(); i=0; l=""
-for a in ${A[@]}; do B[a]=$((++i)); done
+for a in "${A[@]}"; do B[a]=$((++i)); done
 while [ $i -lt 2020 ]; do
     n=$((i-${l:-$i})); l=${B[n]}; B[n]=$((++i))
 done
@@ -16,7 +16,7 @@ sharded_swap() { # syntax: l=B[$1]; B[$1]=$2
 }
 SECONDS=0
 trap 'echo "$i: $SECONDS sec $((i/300000))%"' USR1 EXIT
-i=0; for a in ${A[@]}; do sharded_swap $a $((++i)); done; l="";
+i=0; for a in "${A[@]}"; do sharded_swap "$a" $((++i)); done; l="";
 while [[ $i -lt 30000000 && $SECONDS -le $GIVEUP ]]; do
     n=$((i-${l:-$i})); sharded_swap $n $((++i))
 done
@@ -25,7 +25,7 @@ if [ $i = 30000000 ]; then
 else
     # The code above is painfully slow. Switch to awk
     echo "15B(round $i): $n (Gave up after $SECONDS seconds)"
-    printf "%s\n" ${A[@]} | awk '{B[$0]=++i;}
+    printf "%s\n" "${A[@]}" | awk '{B[$0]=++i;}
 END {
     while (i<30000000) { n=l?(i-l):0; l=B[n]; B[n]=++i; }
     print "15B(awk):", n;