World of A1200/World_Of_A1200.iso/programs/system/csh/tips.doc

Text File | 1995-02-27 | 6KB | 210 lines

Some random tips & tricks I collected:


    EDITING


The very common situation:
$ mkdir documents
$ cd documents
can be abbreviated to:
$ mk documents
$ [CTRL-T]              (inserts all but first word of previous line)


Also very common:
$ mv document document1
$ mv document[CTRL-P]1
The CTRL-P function duplicates the previous word on the command line


You  might  have  wondered  what  CTRL-N  (leave current line) is good for.
Assume, for example, you just typed
$ rm dh1:graphics/lo-res/gorilla
when  it comes to your mind that would prefer to keep a copy of that pic on
diskette.  Many would now delete this command line.  Being a smart guy, you
do the following:
$ [CTRL-N]              (leaves this command line alone)
$ co[CTRL-T] df0:
$ [Up-Arrow][Up-Arrow]  (gets back the command line you left)


In case you don't know what history completion is:
$ search *.c *.h makefile foobar
$ ram:
$ dir
$ rm tmpfile
Now if want to repeat the search command, enter
$ se[Shift-Up-Arrow]
which brings up the the last command that started with 'se'.


If you ever cycle too far using the TAB key, skipping the entry you
orignally wanted, you can get back one entry using CTRL-U [undo].
The same applies if you entered an abbreviation, press TAB but get
aware that the abbrev was too short.


If you want to delete the file
$ rm dh2:comm/uucp/mail/junk/409
and you're far away from that directory, enter
$ rm ju[ESC-c]409          (enters the resulting path of cd ju)


The  same function is also usable for 'cd'.  Assume you have several 'junk'
directories:
$ ju[ESC-c][CTRL-R][CTRL-R][CTRL-R]
Like  this  you'll cycle through the junk directories.  When you've got the
right one, press enter.


Assume  there  are the files comm1.c, comm2.c, and comm3.c as well as their
corresponding .o files.  You want comm3.c:
$ co[Shift-Tab]1[Tab]
Of course this is more useful with longer file names.


You can tab file name expand any patterns, not only abbreviations.  Assume
you want to delete all .c files in the current directory but the last:
$ rm *.c[ESC-Tab][CTRL-W]
In addition, you get to see all the files once again before deleting them.


Next one: You have entered:
$ dir
$ foreach i ( *.c ) "e >>ram:temp $i
$ more ram:temp
and you would like to execute the same three statements again, enter:
$ [Up-Arrow][Up-Arrow][Up-Arrow][ESC-Return][CTRL-R][CTRL-R]


I  know  that  the editing is not very user friendly.  This is because it's
quite  hard  and troublesome to get raw keycodes from the console, and it's
impossible  to  get  them  from a VT200 terminal.  Therefore I had to stick
with CTRL and ESC combinations. Once you have learnt them (some of them are
similar to EMACS), you can save lots of typing.


    COMMANDS


My  advice  here  is clear:  Use aliases, aliases, aliases.  In order to be
able  to  create  them as quickly as possible, create an alias (e.g.  'le')
that edits your login file, plus another one (e.g.  'lx'), that re-executes
it.   My  login  contains  almost  only aliases, everthing else I've put in
'firstlogin.sh'.


If you don't like the default options of one command, you can add more of
them using an alias:
$ alias dir "dir -q
From now on, blocks will no longer be displayed in 'dir'.


If your aliases have arguments, e.g.
$ alias sc "search *.c
problems arise when you try to specify options. e.g. case sensitivity:
$ sc -c "hello world
this will obviously not work. That's what @pickopts is good for:
$ alias sc "%a search @pickopts( $a ) *.c @pickargs( $a )


Once you have more aliases, it is useful to keep them sorted.  You might
also document them: Create a file 'aliases.doc', and perform
$ set _man aliases.doc csh.doc
That way, you can document them in a separate file.


If you would like to create aliases that accept arguments, you can implement
them using 'if -o'.
$ alias good "%a if -o v $a;echo -n "very ";endif;echo good work, @arg( $a )
$ good sam          --> good work, sam
$ good -v sam       --> very good work, sam


'cat' can be used to create small text files:
$ cat >myfile
hello
[CTRL-\]
The key combination CTRL-\ creates an end-of-file character.


    FUNCTIONS


@age is very useful for archiving scripts:
$ foreach i ( * ) "if @age( $i ) > 30;cp -m $i backup:;endif


@clinum can be used for making 'break' and 'pri' more flexible:
$ alias break "%a break @clinum( $a )
Now you can, for example, 'break cc'. Cli numbers are still allowed.


@complete simulates the effect of tab file name completion. That
way, you need no longer press TAB for it:
$ alias edit "%a ced @complete( $a * )


@confirm can be used for a safe 'rm':
$ alias rm "%a rm @confirm( $a )


@howmany is useful at startup:
$ if $howmany = 1;window -l;endif


@intersect, @union and @without are well suited for a lot of applications.
If you store, for example, all files a friend of yours owns, in the variable
$him, (he can do a 'dir -np .../ >temp', you then do a 'readf him <temp'),
and your files in $me, then you can learn what he has and you don't using
$ echo @without( $him , $me )
To ignore different path names, use
$ set him @basename( $him )
If you have the the file names without the path, you can find out the path
by 'search'ing the file temp.


@opt and @arg are needed whenever you have an alias that already specififies
some arguments, but allows the user to specify additional options.
$ alias sc "%a search @opt( $a ) *.c @arg( $a )


@volume can be used to test if there is a disk in a certain drive. It will
suppress requesters and return an empty string if no disk present.


    VARIABLES


$_except can be made local. In that case you have a special exception
handling for the current alias or batch file.


$_man may contain the names of more than one .doc file. That way, you
may add documentation to your own aliases.


When working with large files in pipes, you might want to set $_pipe
to a directory on your hard disk.


    PARSER


If you need to append a string to a variable, you can do it like this:
$ set foo bar
$ echo $foo""bara    --> barbara
The "" isn't necessary if the first character of the string to be appended
is neither a letter nor digit nor _.


To make sure no internal command is executed, capitalize the first letter
of your command:
$ Dir ram: ALL


To override existing aliases to a command, enter:
$ alias echo "xxxxxx
$ \echo hello    -->  hello