*** empty log message ***

LDP/guide/docbook/abs-guide/exercising-dd.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+# exercising-dd.sh
+
+# Script by Stephane Chazelas.
+# Somewhat modified by document author.
+
+input_file=$0   # This script.
+output_file=log.txt
+n=3
+p=5
+
+dd if=$input_file of=$output_file bs=1 skip=$((n-1)) count=$((p-n+1)) 2> /dev/null
+# Extracts characters n to p from this script.
+
+# -------------------------------------------------------
+
+echo -n "hello world" | dd cbs=1 conv=unblock 2> /dev/null
+# Echoes "hello world" vertically.
+
+exit 0

LDP/guide/docbook/abs-guide/multiple-processes.sh

@@ -0,0 +1,71 @@
+#!/bin/bash
+# multiple-processes.sh: Run multiple processes on an SMP box.
+
+# Script written by Vernia Damiano.
+# Used with permission.
+
+#  Must call script with at least one integer parameter
+#+ (number of concurrent processes).
+#  All other parameters are passed through to the processes started.
+
+
+INDICE=8        # Total number of process to start
+TEMPO=5         # Maximum sleep time per process
+E_BADARGS=65    # No arg(s) passed to script.
+
+if [ $# -eq 0 ] # Check for at least one argument passed to script.
+then
+  echo "Usage: `basename $0` number_of_processes [passed params]"
+  exit $E_BADARGS
+fi
+
+NUMPROC=$1              # Number of concurrent process
+shift
+PARAMETRI=( "$@" )      # Parameters of each process
+
+function avvia() {
+	local temp
+	local index
+	temp=$RANDOM
+	index=$1
+	shift
+	let "temp %= $TEMPO"
+	let "temp += 1"
+	echo "Starting $index Time:$temp" "$@"
+	sleep ${temp}
+	echo "Ending $index"
+	kill -s SIGRTMIN $$
+}
+
+function parti() {
+	if [ $INDICE -gt 0 ] ; then
+		avvia $INDICE "${PARAMETRI[@]}" &
+		let "INDICE--"
+	else
+		trap : SIGRTMIN
+	fi
+}
+
+trap parti SIGRTMIN
+
+while [ "$NUMPROC" -gt 0 ]; do
+	parti;
+	let "NUMPROC--"
+done
+
+wait
+trap - SIGRTMIN
+
+exit $?
+
+: << SCRIPT_AUTHOR_COMMENTS
+I had the need to run a program, with specified options, on a number of
+different files, using a SMP machine. So I thought [I'd] keep running
+a specified number of processes and start a new one each time . . . one
+of these terminates.
+
+The "wait" instruction does not help, since it waits for a given process
+or *all* process started in background. So I wrote [this] bash script
+that can do the job, using the "trap" instruction.
+  --Vernia Damiano
+SCRIPT_AUTHOR_COMMENTS

LDP/guide/docbook/abs-guide/quote-fetch.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+# quote-fetch.sh: Download a stock quote.
+
+
+E_NOPARAMS=66
+
+if [ -z "$1" ]  # Must specify a stock (symbol) to fetch.
+  then echo "Usage: `basename $0` stock-symbol"
+  exit $E_NOPARAMS
+fi
+
+stock_symbol=$1
+
+file_suffix=.html
+# Fetches an HTML file, so name it appropriately.
+URL='http://finance.yahoo.com/q?s='
+# Yahoo finance board, with stock query suffix.
+
+# -----------------------------------------------------------
+wget -O ${stock_symbol}${file_suffix} "${URL}${stock_symbol}"
+# -----------------------------------------------------------
+
+exit $?
+
+# Exercises:
+# ---------
+#
+# 1) Add a test to ensure the user running the script is on-line.
+#    (Hint: parse the output of 'ps -ax' for "ppp" or "connect."
+#
+# 2) Modify this script to fetch the local weather report,
+#+   taking the user's zip code as an argument.

LDP/guide/docbook/abs-guide/self-copy.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+# self-copy.sh
+
+# This script copies itself.
+
+file_subscript=copy
+
+dd if=$0 of=$0.$file_subscript 2>/dev/null
+# Suppress messages from dd:   ^^^^^^^^^^^
+
+exit $?