More 2 Cent Tips & Tricks Issue 11

| #### "Linux Gazette...making Linux just a little less scary! " # More 2¢ Tips! Send Linux Tips and Tricks to gazette@ssc.com. ### Contents: Another XTerm Title Trick File Decompression Quick Tricks from John Fisk Two Tips for the Price of One The Ultimate Emacs Control M Trick VI Trick XDM Replacement

| ### Another XTerm Titlebar Trick Date: Wed, 2 Oct 1996 16:11:35 -0700 (PDT) From: Jonathan Gross jong@ssc.com I have a quick stupid shell script to change the titlebar on the fly:
    #!/bin/bash
    echo "]0;$1"
where the ^[ is done in Emacs by typing C-q Esc and the ^G is done by typing C-q C-g, or in vi by typing C-v instead of C-q before each control sequence. Then you type:
    linux$ titlebar "string for window title"
Where "titlebar" is the name of your shell script. Dumb, simple, but easy to use...
    Jonathan Gross
    Specialized Systems Consultants, 206-782-7733
    "A jewel mine of courtesies and a living casket of diplomacy"

| ### File Decompressing Date: Fri, 27 Sep 1996 08:32:37 +0200 (MET DST) From: Xabier Vazquez Gallardo, sixconse@sc.ehu.es Hi there: Here is a script I wrote two years ago, but I think it can be useful for everybody. It can also help in learning shell script programming. The function of this script is to help ppl decompressing compressed files with tar, gzip, compress, arj, zip, etc, and any combination of these compression tools. Just type "gus filename" and the script will call the necessary decompression program. Thanx in advance, Xabier Vazquez Gallardo
    ------------ 8< --------- 8< ---------- 8< ----------- 8< ------------
    #!/bin/sh
    # If you are under ULTRIX use /bin/sh5 instead of /bin/sh (too buggy)
    ################################################################################
    # @(#)gus,v 2.8 11/22/1994 (c) XaBier Vazquez Gallardo
    # You'll need this external programs:
    # gzip, tar, sed, awk, unarj, lha, zoo, unzip, test, pgp, uncompress, echo and
    # uudecode. If you don't have all those programs maybe gus won't work.
    #
    # Program Description:
    # Decompress all this kind of files and combinations of them:
    # .arc .zip .ZIP .arj .zoo .lzh .lha .lzh .Z .z .tar .tgz .shar .pgp
    # .[1-8ln] .man .uu and .uue
    # * Man type files will be displayed
    #
    # Please send suggestions or gub reports to XaBi
    # Sorry about my English, but it's better than Spanish, isn't it?
    ################################################################################
    gus_version="V2.8"
    gus_date="11/22/1994"

    # Show a long help :)
    do_help ()
    {
     echo
     echo This script helps you decompressing Unix archives compressed with compress,
     echo gzip, tar, shar, lha, arj, zip, zoo, pgp, arc and uuencode. It also formats
     echo manual pages. Now you don\'t need to type all those long lines to decompress
     echo a tar + gz archive, only type \'gus file\' and it will do all the work.
     echo "GUS knows this extensions and combinations of them (tar + gzip, etc):"
     echo ".Z .z .zip .arj .zoo .arc .lha .lz .pgp .tar .tgz .shar .[1-8ln] .man .uu .uue"
     echo
     echo "USAGE: '`basename $0` [-h | [[-r | -rf] f1 [f2] ...]' will decompress f1, f2, ..."
     echo "       '-h'  show you this help"
     echo "       '-r'  remove with prompt compressed file after decompress it"
     echo "       '-rf' remove without prompt compressed file after decompress it"
     echo "ie:    '`basename $0` file1 -rf file2 file3' will do this:"
     echo "        decompress file[123] and remove file[23] without any ask"
     echo "       *WARNING* Be careful with option '-rf'"
     exit 0
    }

    # Find a file in your path
    # input : "filename"
    # output: $filresult=full_path/filename || $filename="" + error message
    # ie    : findfile zip
    findfile ()
    {
     sifs=$IFS
     IFS=:
     fileresult=""
     for dir in $PATH; do
       test -z "$dir" && dir=.
       if [ -x $dir/$1 ] ; then
          fileresult="$dir/$1"
          break
       fi
     done
     IFS=$sifs
     test -z "$fileresult" && echo ERROR: Can\'t find $1
    }

    # Change status variables
    # input: " | decompress_command_line" \
    #        " decompress_program_name +" \
    #        1 (if gus must create a decompressed file) || 0 (if not) \
    #        1 (if decompress program can pipe it result) || 0 (if not) \
    #        1 (if decompress program accepts stdin pipes) || 0 (if not)
    # output: none
    # ie    : changevars " | tar xvfo -" " tar +" 0 1 1
    changevars ()
    {
     command=$command$1
     message=$message$2
     create=$3
     exit_f=$4
     do_cat=$5
    }

    # Ask Y/N before remove a file
    # input  : "filename"
    # output : $removeit = 0 (if answer is no) || 1 (if is yes)
    # ie     : makeask /usr/local/foo.bar.tar
    makeask ()
    {
     exit_ask=0
     while [ $exit_ask = 0 ] ; do
       echo "Do you want to remove '$1' [Y/N]? \c"
       read yesno
       case $yesno in
         y* | Y*)
           removeit=1
           exit_ask=1
         ;;
         n* | N*)
           removeit=0
           exit_ask=1
         ;;
       esac
     done
    }

    # Check program parameters and count files
    # input  : "command_line_params"
    # output : $total_files=num_of_files_to_process || or help_screen
    # ie     : check_params -rf foo.tar
    check_params ()
    {
     for i in $*
     do
       case $i in
         -rf | -r)
           total_files=`expr $total_files - 1`
         ;;
         -h)
           do_help
         ;;
       esac
     done
    }

    echo GUS $gus_version [$gus_date] General Unpack Shell for Un*x \(c\) XaBi

    total_files=$#

    check_params $*

    if [ $total_files = 0 ] ; then
       echo ERROR: not enough params
       echo "TRY  : `basename $0` -h"
       exit 1
    fi

    if [ $total_files = 1 ] ; then
       echo [ $total_files ] file to process ...
    else
       echo [ $total_files ] files to process ...
    fi

    removefile=0
    promptbefore=0

    for file_tmp in $*
    do
      case $file_tmp in
           -rf)
              removefile=1
              promptbefore=0
              continue
            ;;
           -r)
              removefile=1
              promptbefore=1
              continue
            ;;
      esac
      if test -f $file_tmp ; then
         exit_f=0
         command=""
         message=""
         do_cat=1
         create=1
         file=`basename $file_tmp`
         while [ $exit_f -eq 0 ] ; do
           old_file=$file
           extension=`echo $file | sed -e 's/.*\.//'`
           if [ "$extension" = "$file" ] ; then
              extension=""
           else
              file=`echo $file | sed -e s/\.$extension$//`
           fi
           case $extension in
             tar)
               changevars " | tar xvfo -" " tar +" 0 1 1
             ;;
             Z)
               changevars " | uncompress" " compress +" 1 0 1
             ;;
             z | gz)
               changevars " | gzip -d" " gzip +" 1 0 1
             ;;
             tgz)
               changevars " | gzip -d | tar xvfo -" " tar + gzip +" 0 1 1
             ;;
             uu | uue)
               changevars " | uudecode" " uuencode +" 0 1 1
             ;;
             shar)
               changevars " | sh" " shar +" 0 1 1
             ;;
             zip | ZIP)
               if [ -z "$command" ] ; then
                  findfile unzip
                  test ! -z "$fileresult" && changevars $fileresult " zip +" 0 1 0
               else
                  echo ERROR: Can\'t pipe to unzip. File partialy decompressed.
               fi
               exit_f=1
             ;;
             arj | ARJ)
               if [ -z "$command" ] ; then
                  findfile unarj
                  test ! -z "$fileresult" && changevars $fileresult" x" " arj +" 0 1 0
               else
                  echo ERROR: Can\'t pipe to unarj. File partialy decompressed.
               fi
               exit_f=1
             ;;
             arc | ARC)
               if [ -z "$command" ] ; then
                  findfile arc
                  test ! -z "$fileresult" && changevars $fileresult" x" " arc +" 0 1
     0
               else
                  echo ERROR: Can\'t pipe to arc. File partialy decompressed.
               fi
               exit_f=1
             ;;
             zoo | ZOO)
               if [ -z "$command" ] ; then
                  findfile zoo
                  test ! -z "$fileresult" && changevars $fileresult" x" " zoo +" 0 1 0
               else
                  echo ERROR: Can\'t pipe to zoo. File partialy decompressed.
               fi
               exit_f=1
             ;;
             lzh | lha | lz | LZH | LHZ | LZ)
               findfile lha
               test ! -z "$fileresult" && changevars " | "$fileresult" x -" " lha +" 0 1 1
               exit_f=1
             ;;
             pgp)
               findfile pgp
               if [ ! -z "$fileresult" ] ; then
                  changevars " | "$fileresult " pgp +" 0 0 1
               else
                  exit_f=1
               fi
             ;;
             [1-8nl] | man)
               test -z "$command" && changevars " | nroff -man | more" " man +" 0 1 1
               exit_f=1
             ;;
             *)
               exit_f=1
             ;;
           esac
         done
         test $create -eq 1 && command=$command" > "$old_file
         if [ -z "$message" ] ; then
             echo ERROR: Don\'t know how to handle [ $file_tmp ]
         else
             message=`echo $message | sed -e 's/ +$//'`
             echo "File [ `basename $file_tmp` ]"
             echo "Type [ $message ]"
             if [ $do_cat = 1 ] ; then
                command="cat "$file_tmp" "$command
             else
                command=$command" "$file_tmp
             fi
             eval $command && {
               if [ $removefile = 1 ] ; then
                  if [ $promptbefore = 1 ] ; then
                     makeask $file_tmp
                     test $removeit -eq 1 && rm -f $file_tmp
                  else
                     rm -f $file_tmp
                  fi
               fi
             } || echo ERROR: [ $file_tmp ] can\'t decompress ...
         fi
      else
         echo ERROR: [ $file_tmp ] Can\'t process it! Exists????
      fi
    done

| ### Quick Tips from John Date: Tue, 08 Oct 1996 08:18:39 -0500 (CDT) From: John M. Fisk fiskjm@ctrvax.Vanderbilt.Edu I recently ran across a "Quick Tip" that might be useful to anyone using the BASH shell. There's a rarely mentioned but very useful feature that's included with it: an online help function that describes all of its built-in functions. To use it you simply invoke it as:
    	% help <builtin>
and it displays a brief usage message. To get a listing of all of the topics that are available, simply type in:
    	% help
This displays a listing of all of BASH's builtin functions. So, for example, if you were interesting in using the "getopts" builtin in order to parse command line options for a shell script, you'd invoke the help function as:
    	% help getopts
which prints a helpful summary of the function and its invocation. The other thing I recently ran across was the use of the "$()" construct in BASH shell programming. When I first started learning shell programming the construct which I'd seen used for command substitution was something like:
    	DATE=`date + "%A %B %C"`
which assigned the output of the date command to the variable DATE. I recently read that this has been deprecated and the accepted construct now for command substitution is the use of the dollar sign and parentheses. The above statement should now be written as:
    	DATE=$(date + "%A %B %C")
which has the same effect. This works under both BASH and the Korn shell (I'm not sure if this also works with C-shell derivatives). ____________________________________________________________John M. Fisk

| ### Two Tips for the Price of One Date: Fri, 4 Oct 1996 18:28:05 -0500 (CDT) From: David Ishee ishee@erc.msstate.edu Just looking at your $0.02 tips and I had some $0.01 tips to add. I liked the perl trick for removing Control-M characters so I made it an alias in my .cshrc file (for the tcsh shell):
    alias tu "perl -pi.bak -e 's/\r//g;' \!^"
Now type "tu filelist" to run the above command. (tu stands for to Unix) Another $0.01 tip: When I used the xterm title bar thingy and I was at a VT, the escape characters would just cause the Linux terminal to beep at me. I now have this in my .cshrc (for the tcsh shell):
    if ($TERM == "xterm") then
      alias precmd 'echo -n "\033]2;"`whoami`":"`pwd`"\007"'
    endif
This puts my login_name:directory in my title bar, but not when I go to a Linux VT.
    +--------------------------------------------------------------------+
    | David Ishee                             ishee@erc.msstate.edu      |
    | Mechanical Engineering Senior                                      |
    | Mississippi State University             OS/2 and Linux user       |
    +------------- http://www2.msstate.edu/~dmi1/index.html -------------+

| ### The Ultimate Emacs Control M Trick Date: Thu, 3 Oct 1996 10:19:24 -0700 From: Rick Bronson rick@efn.org Hi, Here is the ultimate Emacs Control M Trick: Put the following line in your .emacs file:
    (require 'dos-mode)
and have dos-mode.el, which for me is in ~/lisp/dos-mode.el, some where in your path by putting the following line in your .emacs file:
    (setq load-path (append load-path (list "/home/rick/lisp")))
That's it! Now you can edit native DOS files without having to do any conversion at all. You won't see any ^M stuff in the DOS files, they are removed for you. You can cut and paste between DOS and UNIX buffers and the ^M stuff is handled automatically. dos-mode.el is available in /ftp@archive.cis.ohio-state.edu:/pub/gnu/emacs/elisp-archive/modes as dos-mode.el.Z
                                                                           _
                                                                          | |
                                                                          / /__
    .------------------------------------------------------------._______/ (___)
    | Rick Bronson   rick@efn.org   Tel 541-465-9008      _o_    |         (___)
    | Invivo Research       http://www.efn.org/~rick      \|/    |_______  (___)
    | 745 Foothill Drive       "Onde esta dinheiro?"     `---'   |       \_(___)
    | Eugene, OR  97405-4651    -- Gal Costa          Disk | Golf|
    `------------------------------------------------------------'

| ### VI Trick Date: Sat, 26 Oct 1996 05:11:34 -0500 From: John R. Potter jrpotter@neosoft.com I thought you might be interested in my favorite vi trick, which is not a vi trick at all. I spend a lot of time in vi edit sessions, usually with two files open moving data between them using the named buffers. Often someone will come in with a 'brush fire' that needs immediate attention and I really don't want to quit my edit session and lose my buffers. So I put it to sleep with Control Z. You can start up another vi edit session, complete with named buffers and everything. They are two complete separate sessions with no ties between them. When the fire is under control you can bring back the original session with 'fg'. I know this is a very simple thing, but for a long time I didn't know you could do it so I would quit the original session. - John Potter

| ### XDM Replacement Date: Thu, 03 Oct 1996 23:26:00 -0400 From: Jim Nicholson pcks@cnj.digex.net I'm not sure how well known it is in the Linux community, but Pierre Ficheux (pierre@ai.alienor.fr) has written a replacement for the XDM logon dialog that lets you set up icons for users - sort of like what you can do on an SGI machine. The file can be had via ftp://ftp.ibp.fr/pub/linux/tsx-11/sources/usr.bin.X11/xdm-photo-1.1.tar.gz; more info is available on Pierre's web site http://alienor.fr/~pierre/index_us.html - Jim Nicholson ##### This page maintained by the Editor of Linux Gazette, gazette@ssc.com Copyright © 1996 Specialized Systems Consultants, Inc.