Classes 24-25 review (07/15-16/2002)
- Everything you ever wanted to know about
PERL
substitution, with g for global and i for ignore case. Good
review of PERL arrays too. You could even learn something
about output redirection operators (DOS or UNIX) and
the Unix cat command options too.
- Monday email summary note.
- Tuesday email summary note.
- Tuesday example PERL,
which opens a file for input that is not in the same directory
as the PERL program, but in its PARENT .. directory.
[jacobson@math-cs 088]$ ls ../c088*
../c088.html ../c088first4wks.html
../c088PERLsummer2001.html ../c088firstHalf.html
[jacobson@math-cs 088]$ pwd
/home/jacobson/web/088
- View the Source, to see .. used in HTML, to link to a file
in the parent folder's js folder, like this:
../js/makeJavaScript.txt
is the link with hypertext indicating the underlying anchored
reference specification from A HREF=theURL.
- JavaScript
debugger program for Netscape. Notice name for software!
After exporting the Monday and Tuesday email notes from pine
as
emailJuly15th.txt and
emailJuly16th.txt, which
creates the .txt files in my home directory,
how did I move them into my jacobson/web/088 folder???
Note that the web folder's 088 folder was my current directory.
cd .. would do what? Go to 088's folder's parent directory.
cd .. closes the 088 folder (subdirectory) and moves you
to 088's parent, .., which is web.
cd .. at that point, would move you to the ~ or home directory,
which in my case would be jacobson or else venkman
on my student test account.
So how did I move the two emailJuly*.txt files from the jacobson
folder to the current directory, which was jacobson/web/088?
[jacobson@math-cs 088]$ mv ~/emailJuly* .
[jacobson@math-cs 088]$ pwd
/home/jacobson/web/088
pwd stands for present working directory
- - -
p w d
Whatever that present working directory is, you can refer to it
as .
and you can refer to its parent directory as ..
mkdir newDirectory
cd newDirectory
[jacobson@math-cs 088]$ mkdir newDirectory
[jacobson@math-cs 088]$ cd newDirectory
[jacobson@math-cs newDirectory]$ ls -a
. ..
[jacobson@math-cs newDirectory]$
[jacobson@math-cs newDirectory]$ cp ../class22.html .
[jacobson@math-cs newDirectory]$ ls -a
. .. class22.html
[jacobson@math-cs newDirectory]$
[jacobson@math-cs newDirectory]$ cp ~/web/c088.html .
[jacobson@math-cs newDirectory]$
[jacobson@math-cs newDirectory]$ ls -a
. .. c088.html class22.html
[jacobson@math-cs newDirectory]$ ls -al
total 16
drwxr-xr-x 2 jacobson cns_fac 4096 Jul 16 17:25 .
drwx--x--x 3 jacobson cns_fac 4096 Jul 16 17:23 ..
-rw-r--r-- 1 jacobson cns_fac 3146 Jul 16 17:25 c088.html
-rw-r--r-- 1 jacobson cns_fac 1548 Jul 16 17:24 class22.html
[jacobson@math-cs newDirectory]$ pwd
/home/jacobson/web/088/newDirectory
The fastest way to get back to your home directory, is
cd
Another way, is
cd ~
The slowest way here from the newDirectory folder, would be
cd .. You are now in 088 folder
cd .. You are now in web folder
cd .. You are now in the jacobson or home directory folder
[jacobson@math-cs newDirectory]$ pwd
/home/jacobson/web/088/newDirectory
The .. of newDirectory is 088, and
the .. of 088 is web, and
the .. of web is jacobson. Read .. as parent.
For every .., . is the child, when you do
ls -a in
Unix and
see the normally
hidden .. and .
listings.
Here is a DOS and Windows command prompt example
illustrating the same thing, with a Windows high density diskette
being the magnetic media stored in the A: drive.
A:\> md Summer2002
A:\> cd summer2002
A:\Summer2002> dir
Volume in drive A has no label
Directory of A:\Summer2002
. 07-16-02 5:32p . Current directory .
.. 07-16-02 5:32p .. Parent directory ..
0 file(s) 0 bytes
2 dir(s) 1,404,416 bytes free
A:\Summer2002> copy C:\perl\bin\movie*.p .
C:\perl\bin\movies.p
C:\perl\bin\movies2.p
C:\perl\bin\movies3.p
3 file(s) copied
A:\Summer2002> dir
Volume in drive A has no label
Directory of A:\Summer2002
. 07-16-02 5:32p .
.. 07-16-02 5:32p ..
MOVIES P 281 07-16-02 2:40p movies.p
MOVIES2 P 201 07-30-01 10:47p movies2.p
MOVIES3 P 561 07-30-01 11:24p movies3.p
3 file(s) 1,043 bytes
2 dir(s) 1,402,368 bytes free