| From: Karl Carlile <futurus at eircom.net>
| Date: Fri, 15 Jul 2005 21:13:28 +0100
| I have been seriously applying myself to BASH and an
| still not certain what the benefits in mastering it are.
knowing a little bit about bash(1) will, among other things:
(a) assist in _using_ Linux. each terminal window (e.g.)
is running bash. (pedants: you know what I mean!)
you cannot always avoid what is called the command-line
in Linux; "the command-line" means a terminal window;
and that mean `bash'.
(b) many configuration files, useful tips, and so on are
all written in bash. if you ever need to change one,
having some idea what the stuff means is a good idea.
(c) a huge number of applications use bash somewhere at
some time during normal operation (not to mention
also during installation). you may not care about
that, unless you want to write, fix, or contribute
to an application. that "application" might just
quite possibly be a small thingie you need to solve
some problem (that is perhaps what most scripts are
written to do — being able to cook up a script to
deal with some issue is a valuable skill saving
lots of time and frustration). then you may very
possibly need to have a working understanding of
(d) improve your knowledge. (and your job prospects, if
working in software et.al. industry interests you.)
except, perhaps, for `d', none of what I have listed above
(which is by no means complete!) requires you to be a bash
expert. IMHO, `c' should, but the general quality of far
too many bash scripts is so poor (again, IMHO) knowing what
you are doing seems to be a minority opinion.... ;-(
| There is emacs which seems to have s a somewhat different lingo
| to BASH. [ ... ] What are the different functions they each serve.
emacs is an editor. it's purpose is to create and change
text files. (it does a lot more, but at its core, it is
an editor. (pedants: shut up!))
bash is an interpreter (of a class called "shells").
its purpose is to execute applications (programs).
the two programs — bash and emacs — have very different
core (main) purposes.
| [ ... ] Why the different languages. [ ... [
because there are hundreds — thousands — of different
computer languages? ADA, algol, antlr, AWK, B, BCPL,
BASIC, bash, BLISS, C, C++, COBOL, Coral, D, doxygen,
Effiel, FORTRAN, forth, haskell, IDL, Java, JCL, LaTeX,
lex, lisp, make, mortran, mk, m4, nroff, PASCAL, python,
perl, ruby, runoff, SIMULA, sed, SETL, smalltalk, SNOBOL,
TECO, tcl, wml, and yacc, to name a very small number.
each has a purpose, and whilst some are similar or
related or even use each other, most of those I listed
are quite different from one another. and tend to have
variants, with each variation a bit different yet again.
no one or two or three languages is ideal for _all_
purposes. some are toys or just plain stupid, and
others are elegant, and others a mess but useful,
and some really do only one thing (but nominally
do that one thing very very well), and on and on
and on. and on.
e.g., at my job, I invented a small language
specifically designed to test the IDL compiler
I currently maintain. this specialised testing
language is interpreted by an c.1000-line bash
script, which in turn uses sed(1) and make(1)
amongst several other languages, and is itself
nominally run from a PHP(? I think?) script on
an automated machine testing farm, accessed via
a front-end written in HTML.
| Finally are there no online texts that pose problems for
| BASH students so that they can use their knowledge and
| skill to solve them using BASH.
sorry, no idea here (at least, not about on-line
texts-with-exercises). there _are_ some good
hardcopy books with exercises about shell scripting.
(the one I am thinking of especially is, AFAICR,
at work, so I cannot provide a reference until next
week — especially as I can't recall the title! and
it is an older volume, so it may be out-of-print?)
a mentor and studying _good_ scripts is, IMHO, better
than a textbook, but that may not apply to everyone.
if I may guess, you seem to be trying to tackle
many things at once — or at least are conflating
together separate things — and quite understandably
being confused. nothing wrong with that, it is a
natural tendency, but you will very probably make
faster progress of a higher quality and with a
lot more _fun_ if you separate out things as you
learn they are separable. e.g., bash, emacs,
and lisp are all quite separable. pick one,
and study/learn/play with it. or at least try
studying/leaning/playing with each at different
times, rather than all mixed together at once.
Experienced (20+ yrs) kernel/software Eng: | Brian Foster Montpellier,
• Unix, embedded, &tc; • Linux; • doc; | blf at utvinternet.ie FRANCE
• IDL, automated testing, process, &tc. | Stop E$$o (ExxonMobile)!
Résumé (CV) http://www.blf.utvinternet.ie | http://www.stopesso.com
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