the '''http://en.wikipedia.org/wiki/Bourne_shell%|%Bourne Shell''' is one of
the two predominant [Unix shells].



** Reference **

   [http://en.wikipedia.org/wiki/Bourne_shell%|%Wikipedia]:   

   [http://www.in-ulm.de/~mascheck/bourne/%|%The Traditional Bourne Shell Family], Sven Mascheck, 2001-10-07 - 2014-05-03:   

   [http://pubs.opengroup.org/onlinepubs/9699919799/idx/shell.html%|%Shell Command Language], [http://pubs.opengroup.org/onlinepubs/9699919799/%|%The Open Group Base Specifications Issue 7], 2013:   

   [http://pubs.opengroup.org/onlinepubs/009695399/utilities/sh.html%|%sh - shell, the standard command language interpreter], [http://pubs.opengroup.org/onlinepubs/009695399/%|%The Open Group Base Specifications Issue 6], 2004:   



** Implementations **

   [http://heirloom.sourceforge.net/sh.html%|%The Heirloom Bourne Shell]:   


** Variants **

Modern variants of the Bourne Shell include

   ash:   

   [bash]:   
   
   [ksh], by [David Korn]:   a popular Bourne-compatible shell which is also available on [Microsoft Windows%|%Windows].

   zsh:   


** Load or Generate a Tcl [List] **

Here are some shell functions to generate a Tcl list from a sequence of values,
and to load a Tcl list into an array.  They're handy, among other things, for
storing and loading structured data.

======none
#! /bin/env bash

: ${TCLSH:=tclsh}

#generate a Tcl list from a sequence of arguments 
#example: mylist=$(tcllist one two three '{' )
tcllist () {
    local libpath
    local res 
    res=$("$TCLSH" - "$@" <<-'EOF'
        puts [lrange $argv 1 end]
    EOF
    )
    printf %s "$res"
}

#load a Tcl list into an array
#example:  tcllist_arr myarray '{one two {three four} five}'
tcllist_arr () {
    assert declare "$1"
    eval $1'=()'
    while read -d $'\0'; do
        eval $1'[${#'$1'[*]}]="$REPLY"'
    done < <( "$TCLSH" - "${@:2:$#}" <<-'EOF'
        proc main {arg0 argv} {
            set list [lindex $argv 1]
            foreach item $list {
                puts -nonewline $item\0
            }
        }
        main $argv0 $argv
    EOF
    )
}
======



** Why Bourne Shell Is not Fit for Programming **

It is well-known that [csh] is not fit for programming.  Bourne shells also do
not rise to the occasion.  One big issue is their scoping rules.  In the
following example, `$i` in the second function interferes with `$i` in the
first function:

======none
f1 () {
    local i
    for ((i=0 ;i<10 ;i++)); do
        echo $i
        f2
    done
}

f2 () {
    for ((i=0 ;i<5 ;i++)); do
        #do something useful
        :
    done
}

f1
======

----

[PYK] 2015-08-04:  In my opinion, one of the biggest reasons not to write
programs in the Bourne shell language is that subshells swallow errors.  In the
following example, `hello` is not expected to print because the interpreter
should exit when the unknown variable, $k is referenced, and indeed it doesn't:

======
/bin/env sh
set -u
echo $x
echo hello
======

In sh scripting, however, it's extremely common to run commands in a subshell and collect their output.  In the following example, even `hello` does print even though the shell is configured as before: 

======
/bin/env sh
set -u
echo $(echo $x)
echo hello
======

Programming in a dynamic language is already adventurous enough.  At least
choose a sane dynamic language like Tcl.  Beware the ''This is going to be a
smallish script so I'll just write it in sh'' trap. 



** See Also **

   [Playing Bourne shell]:   


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