updated

LDP/guide/docbook/abs-guide/Change.log

@@ -3,6 +3,84 @@ RELEASE HISTORY
 Change log
 
 
+Version 1.4
+'MANGO' release
+06/16/02
+
+1) In "Special Characters" chapter:
+   Added "<" and ">" ASCII comparison entry.
+   Added "\<" and "\>" word boundary in a regular expression entry.
+   Added "&>" to redirection characters.
+   Added "history mechanism" comment to "!" entry.
+
+2) In "Debugging" chapter:
+   Added "missing-keyword.sh" example of error message, with note.
+   Minor language clarification.
+
+3) In "Tests" chapter:
+   Added material to "ex11.sh" example.
+   Changed "cmp a b >/dev/null" inline example to "cmp a b &>/dev/null
+     (thanks Baris Cicek).
+
+4) In "I/O" Redirection chapter:
+   Added "&>filename" to redirection chart.  
+
+5) In "Of Zeros and Nulls" chapter:     
+   Added comment to "suppressing output" inline example.
+
+6) In "External Commands and Filters" chapter:
+   Moved "diff", "patch", "diff3", "sdiff", "cmp", and "comm" from "Text
+   Processing Commands" section to "File and Archiving Commands" section, and
+   created a "Comparison" subsection for them.
+   Moved "ptx" from "Text Processing Commands" section to "File and Archiving
+   Commands" section.
+   Gave the sections descriptive subtitles.
+
+7) In "Text Processing Commands" of "External Commands and Filters" chapter:
+   Added tests to "file-comparison.sh" example.
+   At "head", added "script-detector.sh" example.
+
+8) In "Miscellaneous Commands" section of "External Commands" Chapter:   
+   Added "mcookie" entry.
+
+9) In "Math Commands" section of "External Commands" chapter:
+   At "bc/dc" entry, added "hexconvert.sh" and "factr.sh" (thanks, Michel
+   Charpentier) examples of using "dc."
+
+10) In "List Constructs" chapter:
+    Minor rewriting of "ex65.sh" example.
+
+11) In "Contributed Scripts" appendix:
+    Added "blank-rename.sh" example.
+
+12) In "Writing Scripts" section of "Exercises" appendix:
+    Added detail to "Safe Delete" exercise and moved it to "Medium"
+    subsection.
+    Added "Automatically Decompressing Files" exercise ("Easy" section).
+    Added "Lottery Numbers" exercise ("Easy" section).
+    Added "Passwords" exercise ("Intermediate" section).
+    Added "Fog Index" exercise ("Difficult" section).
+
+13) In the "Security Section" of the "Miscellany" chapter:
+    Added 'Unix Scripting Malware' reference to the footnote.
+
+14) In "Starting off with a Sha-Bang" chapter,
+    Fixed typo in comment in "ex2.sh" example ('wtemp' --> 'wtmp')
+      Thanks for pointing this out, Julien Reveret.
+
+15) In "Internal Commands and Builtins" chapter:
+    At "read" entry, added in-line example of using "cat" to pipe to a
+    "read".
+
+16) In "Optimizations" section of "Miscellany" chapter:
+    Added text.
+
+17) Numerous typos corrected from a list sent in by Andreas Abraham (thanks!).   
+    [Imagine that, I've been misspelling "Eratosthenes" since the 8th grade.]
+
+
+
+
 Version 1.3
 'TANGERINE' release
 06/02/02
@@ -30,7 +108,7 @@ Version 1.3
    Added "Security Issues" section.
    Added Rick Boivie's "pb.sh" script as a recursive script example.
 
-6) In "Optimizations" section of "Miscellany" chapter
+6) In "Optimizations" section of "Miscellany" chapter:
    Editing of "loops" paragraph.
    Added cross-reference to "monthlypmt.sh" script.
 

LDP/guide/docbook/abs-guide/badread.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 #  badread.sh:
-#  Attempting to use 'read'
+#  Attempting to use 'echo and 'read'
 #+ to assign variables non-interactively.
 
 a=aaa

LDP/guide/docbook/abs-guide/ex11.sh

@@ -9,10 +9,30 @@ else
   echo "First command-line argument is $1."
 fi
 
+echo
 
-if [ -z "$1" ]    # Functionally identical to above code block.
-#   if [ -z "$1"   should work, but...
-#+  Bash responds to a missing close bracket with an error message.
+if /usr/bin/test -z "$1"      # Same result as "test" builtin".
+then
+  echo "No command-line arguments."
+else
+  echo "First command-line argument is $1."
+fi
+
+echo
+
+if [ -z "$1" ]                # Functionally identical to above code blocks.
+#   if [ -z "$1"                should work, but...
+#+  Bash responds to a missing close-bracket with an error message.
+then
+  echo "No command-line arguments."
+else
+  echo "First command-line argument is $1."
+fi
+
+echo
+
+if /usr/bin/[ -z "$1"         # Again, functionally identical to above.
+# if /usr/bin/[ -z "$1" ]     # Works, but gives an error message.
 then
   echo "No command-line arguments."
 else

LDP/guide/docbook/abs-guide/ex16.sh

@@ -11,7 +11,8 @@ a=`echo Hello!`   # Assigns result of 'echo' command to 'a'
 echo $a
 #  Note that using an exclamation mark (!) in command substitution
 #+ will not work from the command line,
-#+ since this triggers the Bash "history mechanism".
+#+ since this triggers the Bash "history mechanism."
+#  Within a script, however, the history functions are disabled.
 
 a=`ls -l`         # Assigns result of 'ls -l' command to 'a'
 echo $a           # Unquoted, however, removes tabs and newlines.

LDP/guide/docbook/abs-guide/ex2.sh

@@ -36,7 +36,7 @@ fi
 #    *       ) lines=$1;;
 #    esac
 #
-#* Skip ahead to "Loops" chapter to understand this.
+#* Skip ahead to "Loops" chapter to decipher all this.
 
 
 cd $LOG_DIR
@@ -48,8 +48,8 @@ then
   exit $E_XCD
 fi  # Doublecheck if in right directory, before messing with log file.
 
-# far better is:
-# ---
+# far more efficient is:
+#
 # cd /var/log || {
 #   echo "Cannot change to necessary directory." >&2
 #   exit $E_XCD;
@@ -65,7 +65,7 @@ mv mesg.temp messages             # Becomes new log directory.
 # cat /dev/null > messages
 #* No longer needed, as the above method is safer.
 
-cat /dev/null > wtmp  # > wtemp   has the same effect.
+cat /dev/null > wtmp  #  ': > wtmp' and '> wtmp'  have the same effect.
 echo "Logs cleaned up."
 
 exit 0

LDP/guide/docbook/abs-guide/ex65.sh

@@ -1,25 +1,25 @@
 #!/bin/bash
 
-# "Delete", not-so-cunning file deletion utility.
-# Usage: delete filename
+#  delete.sh, not-so-cunning file deletion utility.
+#  Usage: delete filename
 
 E_BADARGS=65
 
 if [ -z "$1" ]
 then
   echo "Usage: `basename $0` filename"
-  exit $E_BADARGS
+  exit $E_BADARGS  # No arg? Bail out.
+else  
+  file=$1          # Set filename.
 fi  
 
 
-file=$1  # Set filename.
-
-[ ! -f "$1" ] && echo "File \"$1\" not found. \
+[ ! -f "$file" ] && echo "File \"$file\" not found. \
 Cowardly refusing to delete a nonexistent file."
 # AND LIST, to give error message if file not present.
 # Note echo message continued on to a second line with an escape.
 
-[ ! -f "$1" ] || (rm -f $1; echo "File \"$file\" deleted.")
+[ ! -f "$file" ] || (rm -f $file; echo "File \"$file\" deleted.")
 # OR LIST, to delete file if present.
 # ( command1 ; command2 ) is, in effect, an AND LIST variant.
 

LDP/guide/docbook/abs-guide/ex68.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 # sieve.sh
 
-# Sieve of Erastosthenes
+# Sieve of Eratosthenes
 # Ancient algorithm for finding prime numbers.
 
 # This runs a couple of orders of magnitude

LDP/guide/docbook/abs-guide/file-comparison.sh

@@ -2,6 +2,7 @@
 
 ARGS=2  # Two args to script expected.
 E_BADARGS=65
+E_UNREADABLE=66
 
 if [ $# -ne "$ARGS" ]
 then
@@ -9,11 +10,16 @@ then
   exit $E_BADARGS
 fi
 
+if [[ ! -r "$1" || ! -r "$2" ]]
+then
+  echo "Both files to be compared must exist and be readable."
+  exit $E_UNREADABLE
+fi
 
-cmp $1 $2 > /dev/null  # /dev/null buries the output of the "cmp" command.
-# Also works with 'diff', i.e.,   diff $1 $2 > /dev/null
+cmp $1 $2 &> /dev/null  # /dev/null buries the output of the "cmp" command.
+# Also works with 'diff', i.e.,   diff $1 $2 &> /dev/null
 
-if [ $? -eq 0 ]        # Test exit status of "cmp" command.
+if [ $? -eq 0 ]         # Test exit status of "cmp" command.
 then
   echo "File \"$1\" is identical to file \"$2\"."
 else  

LDP/guide/docbook/abs-guide/gen0

@@ -2,8 +2,8 @@
 # --------------------------------------------------------------
 #  The "gen0" file is a 10 x 10 grid using a period (.) for live cells,
 #+ and an underscore (_) for dead ones. We cannot simply use spaces
-#+ for dead cells in this file because of a peculiarity in Bash arrays
-#+ (exercise for the reader: explain this).
+#+ for dead cells in this file because of a peculiarity in Bash arrays.
+#  [Exercise for the reader: explain this.]
 #
 # Lines beginning with a '#' are comments, and the script ignores them.
 __.__..___

LDP/guide/docbook/abs-guide/primes.sh

@@ -2,7 +2,7 @@
 # primes.sh: Generate prime numbers, without using arrays.
 # Script contributed by Stephane Chazelas.
 
-#  This does *not* use the classic "Sieve of Erastosthenes" algorithm,
+#  This does *not* use the classic "Sieve of Eratosthenes" algorithm,
 #+ but instead uses the more intuitive method of testing each candidate number
 #+ for factors (divisors), using the "%" modulo operator.
 
@@ -40,6 +40,6 @@ exit 0
 # Uncomment lines 17 and 25 to help figure out what is going on.
 
 # Compare the speed of this algorithm for generating primes
-# with the Sieve of Erastosthenes (ex68.sh).
+# with the Sieve of Eratosthenes (ex68.sh).
 
 # Exercise: Rewrite this script without recursion, for faster execution.

LDP/guide/docbook/abs-guide/rn.sh

@@ -41,7 +41,11 @@ fi
 exit 0
 
 
-# Exercise:
-# --------
+# Exercises:
+# ---------
 # What type of files will this not work on?
 # How can this be fixed?
+#
+#  Rewrite this script to process all the files in a directory
+#+ containing spaces in their names, and to rename them,
+#+ substituting an underscore for each space.

LDP/howto/docbook/HOWTO-INDEX/appsSect.sgml

@@ -780,7 +780,7 @@ information and implementation details. </Para>
 Apache-Compile-HOWTO</ULink>,
 <CiteTitle>Apache Compile HOWTO (Linux edition)</CiteTitle>
 </Para><Para>
-<CiteTitle>Updated: April 2002</CiteTitle>.
+<CiteTitle>Updated: June 2002</CiteTitle>.
 Describes how to compile the Apache Webserver with
 important modules like mod_perl, mod_dav, mod_auth_ldap,
 mod_dynvhost, mod_roaming, mod_jserv, and mod_php. </Para>

LDP/howto/docbook/HOWTO-INDEX/howtoChap.sgml

@@ -134,7 +134,7 @@ around the 5070 SBUS host based RAID controller by Antares Microsystems.
 Apache-Compile-HOWTO</ULink>,
 <CiteTitle>Apache Compile HOWTO (Linux edition)</CiteTitle>
 </Para><Para>
-<CiteTitle>Updated: April 2002</CiteTitle>.
+<CiteTitle>Updated: June 2002</CiteTitle>.
 Describes how to compile the Apache Webserver with 
 important modules like mod_perl, mod_dav, mod_auth_ldap,
 mod_dynvhost, mod_roaming, mod_jserv, and mod_php. </Para>

LDP/howto/docbook/HOWTO-INDEX/programmSect.sgml

@@ -717,7 +717,7 @@ applications, etc. that work on the Linux platform. </Para>
 Apache-Compile-HOWTO</ULink>,
 <CiteTitle>Apache Compile HOWTO (Linux edition)</CiteTitle>
 </Para><Para>
-<CiteTitle>Updated: April 2002</CiteTitle>.
+<CiteTitle>Updated: June 2002</CiteTitle>.
 Describes how to compile the Apache Webserver with
 important modules like mod_perl, mod_dav, mod_auth_ldap,
 mod_dynvhost, mod_roaming, mod_jserv, and mod_php. </Para>