add some bash functions

functions

@@ -0,0 +1,75 @@
+#Docker: bash into running Docker container
+dockerbash() {
+    docker exec -it $1 bash
+}
+
+#Docker: bash into running Docker container
+dockerlog() {
+    docker logs -f $1
+}
+
+# Simple calculator
+function calc() {
+	local result="";
+	result="$(printf "scale=10;$*\n" | bc --mathlib | tr -d '\\\n')";
+	#                       └─ default (when `--mathlib` is used) is 20
+	#
+	if [[ "$result" == *.* ]]; then
+		# improve the output for decimal numbers
+		printf "$result" |
+		sed -e 's/^\./0./'        `# add "0" for cases like ".5"` \
+		    -e 's/^-\./-0./'      `# add "0" for cases like "-.5"`\
+		    -e 's/0*$//;s/\.$//';  # remove trailing zeros
+	else
+		printf "$result";
+	fi;
+	printf "\n";
+}
+
+# Create a new directory and enter it
+function mcd() {
+	mkdir -p "$@" && cd "$_";
+}
+
+# Run `dig` and display the most useful info
+function digga() {
+	dig +nocmd "$1" any +multiline +noall +answer;
+}
+
+# Search in bash history
+function his() {
+	history | grep --color=auto -i "$1";
+}
+
+# Decompress just about any compressed file format
+function extract {
+ if [ -z "$1" ]; then
+    # display usage if no parameters given
+    echo "Usage: extract <path/file_name>.<zip|rar|bz2|gz|tar|tbz2|tgz|Z|7z|xz|ex|tar.bz2|tar.gz|tar.xz>"
+ else
+    if [ -f $1 ] ; then
+        # NAME=${1%.*}
+        # mkdir $NAME && cd $NAME
+        case $1 in
+          *.tar.bz2)   tar xvjf ../$1    ;;
+          *.tar.gz)    tar xvzf ../$1    ;;
+          *.tar.xz)    tar xvJf ../$1    ;;
+          *.lzma)      unlzma ../$1      ;;
+          *.bz2)       bunzip2 ../$1     ;;
+          *.rar)       unrar x -ad ../$1 ;;
+          *.gz)        gunzip ../$1      ;;
+          *.tar)       tar xvf ../$1     ;;
+          *.tbz2)      tar xvjf ../$1    ;;
+          *.tgz)       tar xvzf ../$1    ;;
+          *.zip)       unzip ../$1       ;;
+          *.Z)         uncompress ../$1  ;;
+          *.7z)        7z x ../$1        ;;
+          *.xz)        unxz ../$1        ;;
+          *.exe)       cabextract ../$1  ;;
+          *)           echo "extract: '$1' - unknown archive method" ;;
+        esac
+    else
+        echo "$1 - file does not exist"
+    fi
+fi
+}