Changes for 9-24-21

index.wiki

@@ -30,6 +30,7 @@ _Ideas.md and Classes.md are encrypted, so these links will not work_
 * [[lang/C++|C++]]
 * [[lang/C-sharp|C#]]
 * [[lang/Python|Python]] 
+* [[lang/Bash|Bash]]
 * [[lang/HTML|HTML]] 
 * [[lang/CSS|CSS]]
 * [[lang/Javascript|Javascript]]

lang/Bash.wiki

@@ -0,0 +1,101 @@
+= Bash =
+
+The shell itself
+
+== Common syntax ==
+
+I tend to forget it sometimes lol
+
+=== Brackets ===
+
+Remember '\[' is a program unto itself. Here are some common flags
+
+* -z 
+ - empty string
+* -n not 
+ - empty string
+* == aka -eq 
+ - equal
+* != aka -ne 
+ - not equal
+* -lt 
+ - less than
+* -gt 
+ - greater than
+* -ge 
+ - greater than or equal
+* !
+ - not
+* && 
+ - and
+* || 
+ - or
+* -e 
+ - file exists
+* -r 
+ - is readable
+* -h 
+ - is symlink
+* -d 
+ - is directory
+* -s 
+ - has data in it
+* -f 
+ - is file
+* -x 
+ - is executable
+
+=== Variables ===
+
+{{{
+var=55
+echo $var
+  }}}
+  
+=== While ===
+
+{{{
+while [ condition ]; do
+    echo "Hello world"
+done
+  }}}
+
+=== Arays ===
+
+{{{
+Fruits={'Apple','Banana','Orange'}
+
+Fruits[0]="Apple"
+echo ${Fruits[0]}
+
+declare -A sounds
+sounds[dog]="bark"
+sounds[cow]="moo"
+sounds[bird]="tweet"
+sounds[wolf]="howl"
+
+echo ${sounds[dog]} # Dog's sound
+echo ${sounds[@]}   # All values
+echo ${!sounds[@]}  # All keys
+echo ${#sounds[@]}  # Number of elements
+unset sounds[dog]   # Delete dog
+  }}}
+
+=== Math ===
+
+{{{
+$((a + 200)) #add 200 to a
+  }}}
+  
+  
+=== Strings ===
+
+{{{
+${FOO%suffix} #remove suffix from foo
+${FOO#prefix} #remove prefix from foo
+${FOO/from/to} #replace first instance of from with to
+${FOO//from/to} #replace all instances of from with to
+${#FOO} #length of foo
+  }}}
+  
+[[index]]

lang/C++.wiki

@@ -14,4 +14,4 @@ drawbacks due to the Object abstraction.
 
 
 
-[[../index]]
+[[index]]

lang/C-sharp.wiki

@@ -5,4 +5,4 @@ Purely object oriented language that relies on a JIT. Primary library is .NET
 
 
 
-[[../index]]
+[[index]]

lang/C.wiki

@@ -4,11 +4,11 @@ Systems language. One of the fastest langs around
 
 == Memory ==
 
-* [[bitwise_cast]] - Cast a type as another bit for bit
+* [[bithacks]] - Wacky was to break memory
 
 
 == Also See ==
 
 [[C++]]
 
-[[../index]]
+[[index]]

lang/bithacks.wiki

@@ -0,0 +1,68 @@
+= Bithacks =
+
+Evil memory manipulation for speed
+
+== Bitwise_cast ==
+
+This works for C/C++. Basically all you do it cast like this
+
+{{{C
+    float cast(int foo){
+        return (* (float*)&foo);
+    }
+}}}
+
+This is also known as the "evil floating point bit level hacking" from the
+quake III fast inverse square root. Great for casting structs as memory for
+hashing, or generally treating one set of bits as another type
+
+== Negating Floats ==
+
+{{{
+    float Negatefloat(float f){
+        return cast_float_to_uint(f) ^ 0x80000000;
+    }
+  }}}
+
+== Fast log base 2 ==
+
+IEE 754 is sci notification of a base 2 value, therefore this works very very
+well. Breaks awfully with negtaives so be sure to check
+
+{{{
+const unsigned int OneAsInt = 0x3F800000;
+const float ScaleUp = float(0x00800000); //2^23
+const float ScaleDown = 1.0f/ScaleUp;
+
+float Log2(float x){
+    return float (cast_float_to_uint(f)-OneAsInt)*ScaleDown
+}
+  }}}
+
+== Fast base 2 exponent ==
+
+This is the opposite of the last one. Does 2^n fast
+
+{{{
+const unsigned int OneAsInt = 0x3F800000;
+const float ScaleUp = float(0x00800000); //2^23
+const float ScaleDown = 1.0f/ScaleUp;
+
+float Log2(float x){
+    return asfloat (cast_float_to_uint(f)*ScaleUp)+OneAsInt;
+}
+  }}}
+  
+== Not accurate square root ==
+
+This doesnt do that well but its better really fast. Does a fast taking of the
+float to the power of 0.5
+
+{{{
+const unsigned int OneAsInt = 0x3F800000;
+float sqrt(float x){
+    return asfloat((asint(x)>>1)+(OneAsInt>>1));
+}
+  }}}
+  
+[[index]]

lang/bitwise_cast.wiki

@@ -1,16 +0,0 @@
-= Bitwise_cast =
-
-This works for C/C++. Basically all you do it cast like this
-
-{{{C
-    float cast(int foo){
-        return (* (float*)&foo);
-    }
-}}}
-
-This is also known as the "evil floating point bit level hacking" from the
-quake III fast inverse square root.
-
-== Uses ==
-
-* Casting structs for hashing

lang/index.wiki

@@ -0,0 +1,20 @@
+= Languages =
+
+== Sections ==
+
+* [[C|C]] 
+* [[C++|C++]]
+* [[C-sharp|C#]]
+* [[Python|Python]] 
+* [[Bash|Bash]]
+* [[HTML|HTML]] 
+* [[CSS|CSS]]
+* [[Javascript|Javascript]]
+* [[PHP|PHP]]
+* [[Rust|Rust]]
+* [[Go|Go]]
+* [[sql|SQL]]
+
+
+
+[[../index]]

sci/Measurment.wiki

@@ -1,6 +1,6 @@
 = Measurment =
 
-This is also the introduction [[chapter]]
+This is also the introduction chapter
 
 == Definitions ==