Bash Problems & Suggestions

[Christopher Buckley]

I'm a newbie to Linux, although not computers. I've
been reading up on bash to see how it works, and
experimenting. I've found parts of the manpage to be
somewhat difficult to comprehend, and have included
some alternative materials. I hope I've understood it
right.

In the meantime, I'm having a problem with a
particular script giving unexplainable results.

I've added the statement ". /bash/all.envir" to the
end of my /etc/profile. The script runs but fails in
the tests of "$LOGNAME". It keeps returning
configurations for "root" even when I logon as "cpmb".
I can't figure out why. Can you help?

ATTACHMENTS ARE:

all.envir

bashupdates.txt

Thanks
Christopher




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# NAME:         all.envir
#
# NOTES:        This file should be used only for global configurations
#                       Do NOT use this one for user specific configurations
#                       Use either ~/.bash_profile or ~/.profile for user 
specific configurations
#
#--------------------------------------------------------------------------------------



if [ -n "$DEBUG_CALLS" ]; then
        if [ "$0"=="-bash" ]; then
                echo BEGIN: all.envir
        else
                echo BEGIN: $0
        fi
fi
#---------------------------------
# BEGIN:
#---------------------------------





# Non-interactive shells dump PS1 on startup
# You should reset PS1 for interactive shells



# FIRST - Set local or global variables
# PATH should only include required paths
PATH=/bin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:/usr/bin/X11

if [ "${LOGNAME}"=="root" ]; then

        echo Root Paths

        PATH=/sbin:${PATH}

        if [ -d /bash ]; then
                PATH=/bash:${PATH}
        fi

else

        echo User Paths

        if [ -d ~/bash ]; then
                PATH=${PATH}:~/bash
        fi
        if [ -d ~/bin ]; then
                PATH=${PATH}:~/bin
        fi
        if [ -d ~/sbin ]; then
                PATH=${PATH}:~/sbin
        fi
        if [ -d ~/man ]; then
                MANPATH=${MANPATH}:~/man
        fi
        
fi



# SECOND - Set local or global modes
mesg n
umask 022
VERSION=`uname -r`



# THIRD - Are we interactive???
if [ "${PS1}" ]; then

        # Setup prompt and common attributes
        PS1="\n\w\t\n${LOGNAME}@\H"
        if [ "$LOGNAME"=="root" ]; then

                echo Root Configs

                PS1="${PS1}$ "
                alias dir='vdir -a | more'
                alias ls='ls -a | more'

        else

                echo User Configs

                PS1="${PS1}# "

                # Directory listing colors
                eval `dircolors`
                alias dir='vdir | more'
                alias ls='ls --color=auto | more'
        
                # Some more alias to avoid making mistakes:
                # alias rm='rm -i'
                # alias cp='cp -i'
                # alias mv='mv -i'

        fi

fi



# FOURTH - Export any variables to sub-shells
export DEBUG_CALLS DEBUG_FLOW PATH PS1 VERSION





#---------------------------------
# EXTRAS:
#---------------------------------

# Check full filename used to invoke
#if [ "$BASH" ]; then
#  PS1='\u@\h:\w\$ '
#else
#  if [ "`id -u`" -eq 0 ]; then
#    PS1='# '
#  else
#    PS1='$ '
#  fi
#fi



# If this is an xterm set the title to user@host:dir
#case $TERM in
#xterm*)
#    PROMPT_COMMAND='echo -ne "\033]0;${USER}@${HOSTNAME}: ${PWD}\007"'
#    ;;
#*)
#    ;;
#esac

# Enable programmable completion features (you don't need to enable
# this, if it's already enabled in /etc/bash.bashrc).
#if [ -f /etc/bash_completion ]; then
#  . /etc/bash_completion
#fi





#---------------------------------
# ERROR HANDLERS:
#---------------------------------





#---------------------------------
# END:
#---------------------------------
# That's all folks!
if [ -n "$DEBUG_CALLS" ]; then
        if [ "$0"=="-bash" ]; then
                echo END: all.envir
        else
                echo END: $0
        fi
fi


         Bash uses a white space separated syntax.
         ALL elements must have separators

        EXAMPLE:
                if ["$LOGNAME"=="root"]; then

        will NOT work. it must be:
        
                if [ "$LOGNAME"=="root" ]; then



INVOCATION & EXIT
    
    Execution

        1) Directory & Script must have execute access rights

        2) PATH must include script folder or use /<path> prefix

        3) Type the name of the script or . name.

        NOTE: Preceeding the name with . will cause it to be sourced.

        EXAMPLES:

                /bash/myscript
                . myscript

    Exit Status
    
       Bash's  exit status  is the exit status of the last
       command executed in the script.  If no commands are
       executed, the exit  status is  0.

    Invocation - Files
    
       /bin/bash
              The bash executable
       /etc/profile
              The  systemwide  initialization  file, executed for
              login shells
       ~/.bash_profile
              The  personal  initialization  file,  executed  for
              login shells
       ~/.bashrc
              The individual per-interactive-shell startup file
       ~/.bash_logout
              The  individual  login shell cleanup file, executed
              when a login shell exits
       ~/.inputrc
              Individual readline initialization file

   Invocation Modes:

       A  LOGIN  shell  is  one which is started by specifying the
       --login option, or is one in which argument zero (the first
       argument following the options list) begins with a - character.

       A NON-LOGIN shell is one which may be started as a subshell or
       CHILD of an existing shell. It may be interactive or non-
       interactive depending upon the calling options.

       An INTERACTIVE shell is one which is started

             1) with its standard input and output both connected
             to terminals (as  determined by  isatty(3))

             2) may have been started with the -i option

             3) and was not started using the -c option

             4) and was not started by specifying any [file], nor
             any other non-optional arguments

       If bash is interactive, PS1 will be set and the parameter $-
       will include "i",  allowing a shell script or a startup file
       to test bash's state.

       A NON-INTERACTIVE shell is one which is started with its
       standard input redirected (to a file or device) and output
       may or may not be connected to terminals. It is generally a
       a NON-LOGIN shell intended to run to completion.

   Invocation Behaviour:

       The  following  paragraphs  describe how bash executes its
       startup files.  If any of the files exist  but  cannot  be
       read,  bash reports an error.  Tildes are expanded in file
       names as described below  under  Tilde  Expansion  in  the
       EXPANSION section.

       When bash is invoked as a LOGIN shell, either interactively
       or as a non-interactive shell using the --login option, it
       attempts to read and and execute commands from specific
       files, according to the following hierarchy:

                1) /etc/profile

                2a) ~/.bash_profile

                2b) ~/.bash_login

                2c) ~/.profile

       Note that for 2a, 2b, and 2c, bash will read commands only
       from the FIRST FILE that exists and is readable. This auto
       configuration behaviour may be inhibited if the option
       --noprofile is specified when the shell is initiated.

       When a LOGIN shell exits, bash attempts to read and execute
       commands from the file ~/.bash_logout, if it exists.

       When a NON-LOGIN shell is started, regardless of interactivity
       bash attempts to read and execute commands from ~/.bashrc,
       if that  file exists.  This may also be inhibited by  using
       the --norc option. The --rcfile file option will force bash to
       read and execute commands from [file] instead  of ~/.bashrc.