Purpose: collect pointers to various Wiki pages that discuss differences, similarities between Tcl and Unix shell scripting languages. Also collect pointers to tools which help in the interactions between the two.
Recently, someone on news:comp.lang.tcl asked for a reference comparing a language such as bash and tcl, to help a bash programmer to learn to program in Tcl. Is anyone aware of such a help/HOWTO/etc.? -> Playing Bourne shell
See Tcl Heritage for some of the influences on Tcl from various sources, including a number of Unix shell languages. See also Tcl and other languages.
http://faqs.org/faqs/unix-faq/shell/shell-differences/ is a web site that (at least for now) discusses differences between several common Unix shells. It would be useful to compare Tcl to those shells to point out commonalities and differences.
For instance, in shells that are derivative of Bourne shell, you assign the stdout of a command using one of these types of notation:
a=`date`
or
a=$(date)
In Tcl, you would type
set a [date]
In Bourne shells, to use a literal with no variable assignments, you would use
a='date'
while in Tcl, you might use
set a {date}or perhaps
set a date
or even
set a "date"
If you want to assign a string including a variable to another variable, you might type
b="$a is a fruit"
while in Tcl you would type
set b "$a is a fruit"