change.log

一本完整的描述Unix Shell 编程的工具书的所有范例

                                   CHANGE LOG
                                       &
                                Release History

                       This file is available on-line at
             http://personal.riverusers.com/~thegrendel/Change.log
------------------------------------------------------------------------

Intermediate update
Working toward version 3.8, blaeberry release

1) In "Variable Substitution" section of "Introduction to Variables and
   Parameters" chapter:
   Added inline example of difference between variable name and value.

2) In "Basic Commands" section of "External Commands" Chapter:   
   At "cp" entry, added example of using -u option.

3) At beginning "Regular Expressions" chapter,
   added Stowe Boyd epigraph.

4) "System and Administrative Commands" chapter:
   In "Job Control" subsection,
     Added "pgrep/pkill. entry.
   In "Filesystem" subsection,
     At "lockfile" entry, more material, including usage example and
     footnote.
     Added "flock" entry.

5) In "File and Archiving Commands" section of "External Commands" Chapter:
   At "sha1sum" entry, added paragraph about security consultants'
   misgivings.

6) In "Parameter Substitution" section of "Variables Revisited" chapter:
   Fixed minor typo at "${parameter:+alt_value}" example.
   (Thank you, Jemshad O K)

7) Partitioned  "Security Section" of the "Miscellany" chapter
   into two subsections.
   Added subsection about "shc" utility for compiling script source.

8) In "Loops" section of "Loops and Branches" chapter:
   Applied fixup to "bin-grep.sh" example.
   (Thank you, Anton Filippov.)

9) Various minor fixups on example scripts.




Version 3.7
Whortleberry release, 10/23/05

1) In "Special Characters" chapter:
   At "whitespace" entry, added footnote about newline/linefeed.

2) In "Basic Commands" section of "External Commands" Chapter:   
   At "ln" entry, noted that only symbolic links can refer to a directory.

3) In "Text Processing Commands" section of "External Commands" Chapter:   
   Modified comments in "wf.sh" example.
   At "grep" entry, fixed 2 typos
      "Now, let's search this file . . . "
      "printf 'a b\nc  d\n\n\n\n\n\000\n\000e\000\000\nf' | grep -cz ."
   At "diff" entry, fixed typo ("spiff" --> "sdiff").
   (Thank you, Frank Wang.)
   At "colrm" entry, changed "warning" to "caution" -- toned it down a bit.
   At "cut" entry,
     Added note about using linefeed as delimiter.
      (Thank you, Jaka Kranjc.)
     Got rid of unnecessary "cat" in inline example.
   At "iconv" entry, added snippet of code from "booklistgen.sh" script.
   (Thank you, Peter Knowles, for permission to use it.)

4) In "Complex Commands" section of "External Commands" Chapter:   
   At "expr" entry, added usage example of escaped parentheses.
   (Thank you, Peter Knowles, for permission to use it.)

5) In "File and Archiving Commands" section of "External Commands" Chapter:
   Added "sha1sum" command at Frank Wang's suggestion.

6) In "Communications Commands" section of "External Commands" chapter:
   In "Remote Host Access" subsection, added "scp" entry.
   Added material at "uucp" entry.
   Added "uux" entry.
   At "wget" listing, added comments.

   At "rsync" entry, fixed up usage example.
   Added "fc4upd.sh" example.
   (Thank you, Frank Wang.)

7) In "Complex Commands" section of "External Commands" Chapter:   
   At "xargs" entry, added footnote about speeding up execution.

8) In "Math Commands" section of "External Commands" chapter:
   Added Frank Wang's comments to "monthlypmt.sh" example.

9) In "Miscellaneous Commands" section of "External Commands" chapter:
   At "tee" entry, redesigned diagram for greater clarity.

10) In "Testing and Branching" section of "Loops and Branches" chapter:
    Rewrote explanation of filename "globbing" in the [list] of a for-loop
    and added comments to "list-glob.sh" example.

11) In "Quoting" chapter:
    Added sidebar near beginning of chapter.
    Removed intro paragraph (superfluous) at beginning of "Quoting Variables"
    section.

12) In "$RANDOM" section of "Variables Revisited" chapter:
    Added comment to "ex21.sh" example.

13) In "Command Substitution" chapter:
    Added footnote about nesting command substitution with backticks
    by using escaping.
    (Thanks, John Default.)

14) In "System and Administrative Commands" chapter:
    Moved "dmesg" entry to "Information and Statistics" subsection.
    In "Process Control and Booting" subsection, added "service" entry.
    At "uptime" entry, added note about load average.
    Fixups at "terminals and modes" sidebar, second example.
    (Thank you, Mark Norman.)

15) In "Bibliography" section:
    Added reference and URL for Col Needham's original IBDB scripts.

16) Numerous typos corrected, per a list sent in by Mark Norman (thanks!).

17) Various changes and fixups in example scripts.





Version 3.6
Pokeberry release, 08/28/05

1) In "Special Characters" chapter:
   At "-" (redirection from/to stdin or stdout [dash]) entry,
   corrected comments.
   (Thank you, Frank Wang.)
   Replaced flawed first example at "brace expansion" entry.
   Added quoting comment at "whitespace" entry.
   
2) In "Operators" subsection of "Operations and Related Topics" chapter:
   Removed unnecessary "echo" from modulo operator usage example.
   (Thank you, Pasha Zubkov.)

3) In "/proc" section of "/dev and /proc" chapter:
   Added comment to "pid-identifier.sh" example, per Teemu Huovila.
   (Thanks!)

4) In "Testing and Branching" section of "Loops and Branches" chapter:
   Changed description of "case" construct from "equivalent of"
   to "analog to" "switch" in C/C++.
   (Thank you, Teemu Huovila.)

5) In "Communications Commands" section of "External Commands" chapter:
   Added "rsync" entry.

6) In "Miscellaneous Commands" section of "External Commands" chapter:
   Added additional usage example at "jot/seq" entry.

7) In "Internal Commands and Builtins" chapter:
   Added "testing 'false'" to "false" entry example.
   (Thank you, Joe Friedrichsen for the suggestion.)
   At "getopts" entry, made corrections in description of behavior of
   $GETOPTS.
   (Thank you, Pharis Monalo.)
   At "source" entry, added notes about passing arguments to "sourced"
   file and using a "return" to pass control back to the calling script.
   Added "caller" entry.

8) In "Contributed Scripts" appendix:
   Made changes to "whx.sh" script.

9) In "Test Constructs" section of "Tests" chapter:
   Fixed up "ex.11.sh" example for difference in Bash 3.x behavior.
   (Thank you, Frank Wang.)

10) In "Internal Variables" section of "Variables Revisited" chapter:
    Fixed up comments in "t-out.sh" example to reflect changes
    in Bash 3.x.
    (Thank you, Frank Wang.)
    Fixed up explanation of "anomalous" output given by ${PIPESTATUS[@]}
    in certain situations.
    (Thank you, Frank Wang, for providing Chet Ramey's explanation.)

11) In "Typing Variables" section of "Variables Revisited" chapter:
    Added caution + example of how "typeset" restricts the scope of a
    variable.
    (Thank you, Michael Iatrou.)


12) In "File and Archiving Commands" section of "External Commands" Chapter:
    At "file" entry, fixed typo (/usrlocal/bin => /usr/local/bin).
    Fixed error in "strip-comments.sh" example script.
    (Thank you, Jesse Gough.)

13) In "Complex Commands" section of "External Commands" Chapter:   
    At "xargs" entry, added extra usage example.
    At "expr" entry, added example of illegal arithmetic operation.

14) In "$RANDOM" section of "Variables Revisited" chapter:
    Added Frank Wang's alternative to jipe's example.

15) In "Quoting" chapter:
    Split the chapter into introduction and "Quoting Variables" and
   "Escaping" sections.

    Corrected note about unquoted "grep" . . .
    Added discussion about quoting correcting echo's appetite for newlines.
    Clarified explanation of referencing quoted variables
    and added footnote.
    Amended tip about double quotes being necessary only to prevent word
    splitting.
    (Thank you, Harald Koenig.)

16) In "Local Variables" section of "Functions" chapter:
    In footnoted example of a segfaulting recursive function,
    added an "echo" to properly exercise the function.
    (Thank you, Dr. Roland Sonnenschein.)

17) In "Debugging" chapter:
    At listing of "Tools for debugging non-working scripts,"
    added list item for "$LINENO" variable and "caller" builtin.

    At "trap" entry, replaced buggy "multiple-processes.sh" example.
    (Thank you, Tedman Eng.)

18) In "Copyright" chapter:
    Updated licensing terms to give the LDP the right to reassign custodianship
    of the book in the event the author cannot be contacted.

19) In "Bibliography" section:
    Added entry for Peter Knowles' booklistgen.sh --
    Sony Librie booklist generator -- making possible
    Linux access to this neat e-book reader.

20) Corrected spelling of the name of contributor St閜hane Chazelas
    in multiple places.
    (Thank you, Bertrand Mollinier Toublet, for pointing out these
    embarrassing typos.)

21) Various changes and fixups in example scripts.



Version 3.5
Boxberry release, 06/05/05



1) In "Indirect References to Variables" section of "Variables Revisited" chapter:
   Added "ugly kludge" sidebar.

2) In "Variable Assignment" section of "Introduction to Variables and
   Parameters" chapter:
     After "ex16.sh" example, noted that $(...) construct is a form of
     command substitution.

3) In "Special Variable Types" section of "Introduction to Variables and
   Parameters" chapter:
     In note about remedies for missing command-line parameters,
     added discussion about using parameter substitution,
     rather than adding extra characters to variable names.
     (Thank you, Fabian Kreutz.)

4) In "Command Substitution" chapter:
   At note at end of chapter, added mention that nesting is possible
   with $(...) construct, and added "agram2.sh" example script.

5) In "Internal Commands and Builtins" chapter:
   At "exec" entry, added footnote and streamlined text.

6) In "File and Archiving Commands" section of "External Commands" Chapter:
   At "more/less" entry, added "testing command sequence" usage example.
   At "mktemp" entry, added usage example and elaborated existing example.

7) In "Communications Commands" section of "External Commands" chapter:
   At "dig" entry, added "spam-lookup.sh" example.

8) In "Text Processing" section of "External Commands" Chapter:   
   At "tail" entry, added usage example of combining "head" and "tail"
   to extract a specific line or lines from a text file.

9) In "System and Administrative Commands" chapter:
   At "umask" entry, added "rot13a.sh" example script.

10) In "Complex Functions and Function Complexities" section of "Functions"
chapter:
    Added in-line example ("days in month") of capturing function "echo"
    as "return value."

11) In the "Shell Wrappers" section of "Miscellany" chapter:
    Added "pr-asc.sh" example script.

12) Changed "Files" chapter into an appendix.

13) In the "Sed and Awk Micro-primer" appendix:
    More examples of the awk "print" command.

14) In "Contributed Scripts" appendix:
    Added "whx.sh" script.
    (Thank you, Walter Dnes.)

15) Miscellaneous fixups and stylistic changes in the text and various
    scripts.
    Fixed up three misspellings of "permissible"!
    Updated morethan.org site address.



Version 3.4
Teaberry release, 05/08/05

1) In "Special Characters" chapter:
   Some minor additions and cleanups.

2) In "Basic Commands" section of "External Commands" Chapter:   
   At "ls" entry, minor fixups on "ex40.sh" example.
   At "rm" entry, added "rm -- -badname" method of deleting hyphen-prefixed
   filenames.

3) In "Time/Date Commands" section of "External Commands" chapter:
   At "date" entry:
     Added mention of "TZ=XXX" option.
     (Thanks, Frank Kannemann and Pete Sj鯾erg.)
     Also added discussion of additional options.

4) In "Communications Commands" section of "External Commands" chapter:
   At "lynx" entry, added paragraph on "-traversal" option.
   At "wget" entry, added comments to "quote-fetch.sh" example script.

5) In "Miscellaneous Commands" section of "External Commands" Chapter:
   At "sox" entry, added links for examples of script use.
   At "getopt" entry, fixed typo.

6) In "Math Commands" section of "External Commands" chapter:
   At "dc" entry, added echoing obfuscated text entry.

7) In "Internal Commands and Builtins" chapter:
   At "echo" entry, added comments to in-line examples of
   embedding linefeed in a string.
   (Per suggestion of Michal Jaegermann.)
   At "hash" entry, added footnote explaining what a hash is.
   Modified "col-totaler3.sh" example script to make it more interesting.
   At "forking" sidebar, added paragraph about parent-child process problem.

8) In "File test Operators" section of "Tests" chapter:
   Added deprecated "-a" option.

9) In "System and Administrative Commands" chapter:

   Added "nc" entry, and
     Added "iscan.sh" example script.
     (Thank you, Hobbit.)

     Added Dr. Andrew Tridgell's famous one-line script.
     (Thank you for permission to quote it, Tridge.)

   At "logrotate" entry, added URL for Stefano Falsetto's "rottlog"
   project.
   At "ps" entry, added graphical "tree" options.