Fuzzy | Fuzzier | Fuzziest

Printing a specific line in a file using sed:

 sed -n '1258p' file.txt 

Printing a range of lines in a file using sed:

 sed -n '1258,1262p' file.txt 

Deleting a single line from a file using sed:

 sed -e '1258d' file.txt > newfile.txt 

Get length of string in Korn Shell (ksh) script:

 printf $str_variable | wc -c

Check if variable is null or empty in Korn Shell (ksh) script:

  if [[ -z "$variable_name" ]] 
  then 
    echo "Very null." 
  fi 

Check if a variable is not equal to a numeric value in a Korn Shell (ksh) script:

  if [[ $numeric_variable -ne 1 ]] 
  then 
    echo "Not equal to 1." 
  fi 

Using the OR operator in a Korn Shell (ksh) if statement:

  if [[ -z "$variable_name" || $numeric_variable -ne 1 ]] 
  then 
    echo "variable_name is null or numeric_variable is not equal to 1." 
  fi 

Check if last command was successful in Korn Shell (ksh):

  if [[ $? = 0 ]] 
  then 
    echo "Success." 
  else 
    echo "Failed." 
  fi 

Find and replace all occurrences of a string using sed (replace "dog" with "cat" and "paw" with "claw"):

sed -e 's/dog/cat/g' -e 's/paw/claw/g' input_file.txt > output_file.txt 

How to accept user input in a Korn Shell (ksh) script:

  echo "Enter your pet's name (on the line below):" 
  read pet_name 
  
  printf "Enter your pet's name (on this line): " 
  read pet_name 
  
  printf "Enter your pet's name (on this line and in a single statement): " && read pet_name