some sytem scripts

shell_scripts/power_user_awk/AWK_TIPS.txt

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+Data Manipulation
+-----------------
+
+
+Print elements in the column 3 that has the word "good" in the other columns
+$ awk '/good/ { print $3 }' inventory
+
+Syntax:
+$ awk -f {PROGRAM FILE} FILENAME
+
+awk program is:
+
+PATTERN{
+  ACTION 1
+  ACTION 2
+  ACTION 3
+}
+
+
+. (Dot) Match any character
+* Match zero or more character
+^ Match beginning of line
+$ Match end of line
+\ Escape character following
+[ ] List
+{ } Match range of instance
++ Match one more preceding
+? Match zero or one preceding
+| Separate choices to match
+
+
+
+IF CONDITION
+------------
+
+if (condition)
+{
+  Statement 1
+  Statement 2
+  Statement N
+  if condition  is TRUE
+}
+else
+{
+  Statement 1
+  Statement 2
+  Statement N
+  if condition is FALSE
+}
+
+
+FOR LOOP
+--------

shell_scripts/power_user_awk/TIPS.txt

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+For files with many columns:
+===========================
+
+$ cut -f2 NAMEFILE  --> display the second column
+$ cut -f1 NAMEFILE  --> display first column
+$ paste FILE1 FILE2  --> join the columns together of two files
+$ join FILE1 FILES2  --> join separate files but only if there is common field in both files with identical values
+
+
+Changing the contend of files:
+==============================
+
+CHARACTERS:
+----------
+
+$ tr "h2" "3x" < FILENAME --> changes all h to 3 and all 2 to x
+
+
+WORDS:
+------
+$ sed expression file
+$ sed '/tea/s//milk/g' FILENAME
+
+/tea/ --> find tea word
+s//milk/ --> replace (substitute) the word milk for tea
+g --> make the changes globally
+
+
+DUPLICATES:
+-----------
+
+Print LINES that are unique.
+$ uniq FILENAME
+
+Duplicate lines must be next to next to each other, so it's better to sort first:
+$ sort FILENAME | uniq
+
+
+Ex
+--
+$ ex FILENAME --> start the editor

shell_scripts/power_user_awk/file_directory_example.awk

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+# awk -f FILEAWK FILELIST
+
+BEGIN{
+}
+
+#
+# main logic is here
+#
+{
+    sfile = $1
+    dfile = $2
+    cpcmd = "cp " $1 " " $2
+    printf "Coping %s to %s\n",sfile,dfile
+    system(cpcmd)
+}
+
+#
+# End action, if any, e.g. clean ups
+#
+END{
+}

shell_scripts/power_user_awk/for_loop.awk

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+# awk -f for_loop.awk
+
+BEGIN {
+   printf "To test for loop\n"
+   printf "Press CTRL + C to stop\n"
+ }
+ {
+  for(i=0;i<NF;i++)
+  {
+       printf "Welcome %s, %d times.\n" ,ENVIRON["USER"], i
+  }
+}

shell_scripts/power_user_awk/math1.awk

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+
+# awk -f math1
+{
+no1 = $1
+no2 = $2
+ans = $1 + $2
+print no1 " + " no2 " = " ans
+}

shell_scripts/power_user_awk/math2.awk

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+# awk -f math2
+
+BEGIN {
+  myprompt = "(To Stop press CTRL+D) > "
+  printf "Welcome to MyAddtion calculation awk program v0.1\n"
+  printf "%s" ,myprompt
+}
+
+{
+no1 = $1
+op = $2
+no2 = $3
+ans = 0
+
+if ( op == "+" )
+{
+     ans = $1 + $3
+     printf "%d %c %d = %d\n" ,no1,op,no2,ans
+     printf "%s" ,myprompt
+ }
+ else
+ {
+     printf "Opps!Error I only know how to add.\nSyntax: number1 + number2\n"
+     printf "%s" ,myprompt
+  }
+}
+
+END {
+    printf "\nGoodbye, %s\n !" , ENVIRON["USER"]
+}