shell: reformatted, fixed inspections, typos (#2506)

Reformatted shell scripts according to [ShellCheck](https://github.com/koalaman/shellcheck/).

I. Most common changes:
1. https://github.com/koalaman/shellcheck/wiki/SC2086
	`$var` → `"$var"`
	Note: this isn't always necessary and I've been careful not to substitute where it wasn't necessary in meaning.
2. https://github.com/koalaman/shellcheck/wiki/SC2006
	`` `command` `` → `$(command)`
3. https://github.com/koalaman/shellcheck/wiki/SC2004
	`$(( $a + $b ))` → `$(( a + b ))`
4. https://github.com/koalaman/shellcheck/wiki/SC2164
	`cd "$dir"` → `cd "$dir" || exit 1`
5. https://github.com/koalaman/shellcheck/wiki/SC2166
	`[ check1 -o check2 ]` → `[ check1 ] || [ check2 ]`
6. https://github.com/koalaman/shellcheck/wiki/SC2002
	`cat "${file}" | wc -c` → `< "${file}" wc -c`
	Note: this looks a bit uglier but works faster.

II. Some special changes:
1. In file `utils/common.sh`:
	https://github.com/koalaman/shellcheck/wiki/SC2112
	This script is interpreted by `sh`, not by `bash`, but uses the keyword `function`.
	So I replaced `#!/usr/bin/env sh` to `#!/usr/bin/env bash`.
2. After that I thought of replacing all shebangs to `#!/usr/bin/env bash` for consistency and cross-platform compatibility, especially since most of the files already use bash.
3. But in cases when it was `#!/bin/sh -e` or `#!/bin/bash -eu` another problem appears:
	https://github.com/koalaman/shellcheck/wiki/SC2096
	So I decided to make all shebangs look uniform:
	```
	#!/usr/bin/env bash
	set -e (or set -eu) (if needed)
	```
4. In file `tests/ossfuzz.sh`:
	https://github.com/koalaman/shellcheck/wiki/SC2162
	`read i` → `read -r i`
	Note: I think that there is no need in special treatment for backslashes, but I could be wrong.
5. In file `tests/do.sh.in`:
	https://github.com/koalaman/shellcheck/wiki/SC2035
	`ls *.*cap*` → `ls -- *.*cap*`
6. In file `utils/verify_dist_tarball.sh`:
	https://github.com/koalaman/shellcheck/wiki/SC2268
	`[ "x${TARBALL}" = x ]` → `[ -z "${TARBALL}" ]`
7. In file `utils/check_symbols.sh`:
	https://github.com/koalaman/shellcheck/wiki/SC2221
	`'[ndpi_utils.o]'|'[ndpi_memory.o]'|'[roaring.o]')` → `'[ndpi_utils.o]'|'[ndpi_memory.o]')`
8. In file `autogen.sh`:
	https://github.com/koalaman/shellcheck/wiki/SC2145
	`echo "./configure $@"` → `echo "./configure $*"`
	https://github.com/koalaman/shellcheck/wiki/SC2068
	`./configure $@` → `./configure "$@"`

III. `LIST6_MERGED` and `LIST_MERGED6`
	There were typos with this variables in files `utils/aws_ip_addresses_download.sh`, `utils/aws_ip_addresses_download.sh` and `utils/microsoft_ip_addresses_download.sh` where variable `LIST6_MERGED` was defined, but `LIST_MERGED6` was removed by `rm`.
	I changed all `LIST_MERGED6` to `LIST6_MERGED`.

Not all changes are absolutely necessary, but some may save you from future bugs.

1 files changed, 15 insertions, 15 deletions

diff --git a/tests/do-dga.sh b/tests/do-dga.sh
index cba03d73d..ca5bcbd9b 100755
--- a/tests/do-dga.sh
+++ b/tests/do-dga.sh
@@ -1,6 +1,6 @@
-#!/bin/sh
+#!/usr/bin/env bash
 
-cd "$(dirname "${0}")"
+cd "$(dirname "${0}")" || exit 1
 
 # Baseline performances ------------------------------------------------------------------------------------------------
 # Important notes: BASE values must be integers examples and represents percentage (e.g. 79%, 98%).
@@ -18,9 +18,9 @@ DATA_SIZE=0
 RC=0
 
 get_evaluation_data_size() {
-  DGA_DATA_SIZE=`wc -l dga/test_dga.csv | awk '{split($0,a," "); print a[1]}'`
-  NON_DGA_DATA_SIZE=`wc -l dga/test_non_dga.csv | awk '{split($0,a," "); print a[1]}'`
-  DATA_SIZE=$(( $NON_DGA_DATA_SIZE + $DGA_DATA_SIZE ))
+  DGA_DATA_SIZE=$(wc -l dga/test_dga.csv | awk '{split($0,a," "); print a[1]}')
+  NON_DGA_DATA_SIZE=$(wc -l dga/test_non_dga.csv | awk '{split($0,a," "); print a[1]}')
+  DATA_SIZE=$(( NON_DGA_DATA_SIZE + DGA_DATA_SIZE ))
 }
 
 evaluate_ndpi_dga_detection() {
@@ -29,25 +29,25 @@ evaluate_ndpi_dga_detection() {
   # Precision: TP / (TP + FP)
   # Recall: TP / (TP + FN)
 
-  TP=`$DGA_EVALUATE dga/test_dga.csv`
-  FN=$(( $DGA_DATA_SIZE - $TP ))
-  FP=`$DGA_EVALUATE dga/test_non_dga.csv`
-  TN=$(( $NON_DGA_DATA_SIZE - $FP ))
+  TP=$($DGA_EVALUATE dga/test_dga.csv)
+  FN=$(( DGA_DATA_SIZE - TP ))
+  FP=$($DGA_EVALUATE dga/test_non_dga.csv)
+  TN=$(( NON_DGA_DATA_SIZE - FP ))
 
-  ACCURACY=`echo "print(int(((${TP} + ${TN})/(${TP} + ${TN} + ${FP} + ${FN}))*100))" | python3`
-  PRECISION=`echo "print(int(((${TP})/(${TP} + ${FP}))*100))" | python3`
-  RECALL=`echo "print(int(((${TP})/(${TP} + ${FN}))*100))" | python3`
+  ACCURACY=$(echo "print(int(((${TP} + ${TN})/(${TP} + ${TN} + ${FP} + ${FN}))*100))" | python3)
+  PRECISION=$(echo "print(int(((${TP})/(${TP} + ${FP}))*100))" | python3)
+  RECALL=$(echo "print(int(((${TP})/(${TP} + ${FN}))*100))" | python3)
 
   # In case modified version of classification algorithm decreases performances, test do not pass.
-  if [ $ACCURACY -lt $BASE_ACCURACY ]; then
+  if [ "$ACCURACY" -lt "$BASE_ACCURACY" ]; then
 		 printf "ERROR: Your modifications decreased DGA classifier accuracy: 0.${BASE_ACCURACY} decreased to 0.${ACCURACY}!\n"
 		 RC=1
   fi
-  if [ $PRECISION -lt $BASE_PRECISION ]; then
+  if [ "$PRECISION" -lt "$BASE_PRECISION" ]; then
 		 printf "ERROR: Your modifications decreased DGA classifier precision: 0.${BASE_PRECISION} decreased to 0.${PRECISION}!\n"
 		 RC=1
   fi
-  if [ $RECALL -lt $BASE_RECALL ]; then
+  if [ "$RECALL" -lt "$BASE_RECALL" ]; then
 		 printf "ERROR: Your modifications decreased DGA classifier recall: 0.${BASE_RECALL} decreased to 0.${RECALL}!\n"
 		 RC=1
   fi