mastering-unix-ss/chapter15/hgrep.bash

#!/bin/bash
#
# SCRIPT: hgrep.bash
# AUTHOR: Randy Michael
# DATE: 07/09/2007
# REV 3.0
# 
# PLATFORM: Not Platform Dependent
#
# PURPOSE: This script is used to highlight text in a file. 
#    Given a text string and a file the script will search
#    the file for the specified string pattern and highlight
#    each occurrence. For standard input the script pages a
#    temporary file which has the string text highlighted.
#
# REV LIST:
#
# set -x   # Uncomment to debug
# set -n   # Uncomment to check script syntax without execution
#
# EXIT CODES:
#       0 ==> Script exited normally
#       1 ==> Usage error
#       2 ==> Input File Error
#       3 ==> Pattern not found in the file
#
# REV LIST:
#    03/12/2001 - Randy Michael - Sr. Sys. Admin.
#    Added code to just exit if the string is not in
#    the target file.
#
#    03/13/2001 - Randy Michael - Sr. Sys. Admin.
#    Added code to ensure the target file is a readable 
#    "regular" non-zero file.
#
#    03/13/2001 - Randy Michael - Sr. Sys. Admin.
#    Added code to highlight the text string and filename 
#    in the error and information messages.
#
#    08-22-2001 - Randy Michael - Sr. Sys. Admin
#    Changed the code to allow this script to accept standard
#    input from a pipe. This makes the script work more like the
#    grep command
#
#    7/02/2007 - Randy Michael - Sr. Sys. Admin
#    Converted this script to BASH shell.
#
##############################################
#     DEFINE FILES AND VARIABLES HERE 
##############################################

SCRIPT_NAME=$(basename $0)
OUTPUT_FILE="/tmp/highlightfile.out"
>$OUTPUT_FILE

##############################################
#     DEFINE FUNCTIONS HERE 
##############################################

function usage
{
echo -e "\nUSAGE: $SCRIPT_NAME  pattern  [filename]\n"
}

##############################################
#        CHECK COMMAND SYNTAX 
##############################################

# Input coming from standard input

if (( $# == 1 ))
then
     # Input coming from standard input

     PATTERN="$1" # Pattern to highlight
     FILENAME=    # Assign NULL to FILENAME

elif (( $# == 2 ))
then
     # Input coming from $FILENAME file

     PATTERN="$1"  # Pattern to highlight
     FILENAME="$2" # File to use as input

     # Does the file exist as a "regular" file?

     if [ ! -f "$FILENAME" ]
     then
        echo -e "\nERROR: $FILENAME does not exist...\n"
        usage
        exit 2
     fi

     # Is the file empty?

     if [ ! -s "$FILENAME" ]
     then
        echo -e "\nERROR: \c"
        tput smso
        echo -e "$FILENAME\c"
        tput sgr0
        echo -e " file size is zero...nothing to search\n"
        usage
        exit 2
     fi

     # Is the file readable by this script?

     if [ ! -r "$FILENAME" ]
     then
        echo -e "\nERROR: \c"
        tput smso
        echo -e "${FILENAME}\c"
        tput sgr0
        echo -e " is not readable to this program...\n"
        usage
        exit 2
     fi

     # Is the pattern anywhere in the file?

     grep -q "$PATTERN" "$FILENAME"
     if (( $? != 0 ))
     then
        echo -e "\nSORRY: The string \c"
        tput smso
        echo -e "${PATTERN}\c"
        tput sgr0
        echo -e " was not found in \c"
        tput smso
        echo -e "${FILENAME}\c"
        tput sgr0
        echo -e "\n\n....EXITING...\n"
        exit 3
     fi
else
     # Incorrect number of command-line arguments
     usage
     exit 1
fi

##############################################
#      BEGINNING OF MAIN 
##############################################

# There is no $FILENAME if we get input from a pipe...

if [[ ! -z "$FILENAME" && "$FILENAME" != '' ]]
then
    # Using $FILENAME as input

    case $(uname) in
    AIX|HP-UX)
      # This is a fancy "pg" command.  It acts similar to the
      # "more" command but instead of showing the percentage
      # displayed it shows the page number of the file

      sed s/"${PATTERN}"/$(tput smso)"${PATTERN}"$(tput sgr0)/g \
      "$FILENAME"  | pg -csn -p"Page %d:"
      exit 0
      ;;
    *)
      sed s/"${PATTERN}"/$(tput smso)"${PATTERN}"$(tput sgr0)/g \
      "$FILENAME" | more
      exit 0
      ;;
    esac
else
     # Input is from standard input...
     sed s/"${PATTERN}"/$(tput smso)"${PATTERN}"$(tput sgr0)/g \
         > $OUTPUT_FILE

     # Is the pattern anywhere in the file?
     grep -q "$PATTERN" $OUTPUT_FILE
     if (( $? != 0 ))
     then
        echo -e "\nERROR: The string \c"
        tput smso
        echo -e "${PATTERN}\c"
        tput sgr0
        echo -e " was not found in standard input\c"
        echo -e "\n\n....EXITING...\n"
        exit 3
     fi
fi

# Check the operating system, on AIX and HP-UX we need to
# use the "pg", or "page" command.  The "more" command does
# not work to highlight the text, it will only show the
# characters that make up the escape sequence.  All
# other operating system usr the "more" command.

case $(uname) in
AIX|HP-UX)

     # This is a fancy "pg" command.  It acts similar to the
     # "more" command but instead of showing the percentage
     # displayed it shows the page number of the file

     cat $OUTPUT_FILE | pg -csn -p"Page %d:"
   ;;
*)
     cat $OUTPUT_FILE | more
   ;;
esac