V7/usr/lib/learn/files.a
eL0 ^ #next
0.1a 10
L0.1a ; #print
This course will help you learn about basic file
handling commands. You should first understand
the special characters # and @:
# cancels the previous character typed;
@ cancels the line being typed.
If you make a typing mistake, you can use these characters to
correct it before you finish the line and the computer won't
ever know about it. For example, what will the
computer really receive if you type
st#he@
thf#e
at it? Reply "answer WORD" where WORD is the word
as it will be interpreted. For example, if
you think it will get 'dog', type
answer dog
If you think it will receive the word "bark", type
answer bark
Don't forget to leave a space between "answer" and the word
and to hit RETURN at the end of the line.
Don't use any quotation marks in your answer.
#copyin
#user
#uncopyin
#match the
#bad answerthe
Leave a space between "answer" and "the".
#log
#next
0.1b 5
L0.1b X E#print
You should also understand a few simple commands.
When UNIX types a "$" at you, you can type a command.
For example, if you type "date" the computer will tell
you the current date and time. If you see "$" and type "who",
UNIX will tell you who is logged on at present. There are
many other commands, too. You must type a RETURN at the
end of each command line.
Try the "date" command now: find out what
date it is, and after the computer has responded, type "ready".
And don't forget the RETURN!
#copyin
#user
#uncopyin
grep date .copy >/dev/null
#bad day
You were supposed to type "date" (without quotes).
The computer is very intolerant of spelling errors.
Try again.
#bad "date"
Don't type those quote marks. Try again.
#bad time
The time command does not tell you the wall-clock time.
Try date next time.
#log
#next
0.1c 5
pL0.1c [ [#print
The computer keeps track of information in "files."
A file might contain a letter to a friend,
or a memo (or part of it) that you are typing,
or any number of other things.
You can list the names of your files
by typing the command "ls".
Try "ls" now; then type "ready".
Remember that each command must go on a separate line
and each line must be ended with RETURN.
#create letter
Dear John:
I'm terribly sorry...
#create memo
This is a memo.
#create memo1
Another memo.
#copyin
#user
#uncopyin
grep '^ls' .copy >/dev/null
#bad "ls"
Don't type the quotes, please. Try again.
#log
#next
0.1d 10
L0.1d \ {#print
File names are essentially arbitrary,
although usually one names files sensibly:
the files that make up a memo
might be called "memo1", "memo2", etc.
The contents of a file are also entirely up to you:
for example, a file named "memo" could contain
Analysis of Irregular Statistics
John B. Pencilpusher
Bell Laboratories, Murray Hill, NJ
....
To get at the information in a file,
you have to use the file name,
which in this case is "memo".
Is there a difference between the name of a file
and the contents of a file?
Type "yes" or "no".
#copyin
#user
#uncopyin
#match yes
#log
#next
1.1a 10
1.2a 5
L1.1a h #print
The "ls" command will list the names of the files
in your directory. Is there a file named "junk"
present? Find out and then type "yes" or "no".
#copyin
#user
#uncopyin
#match no
#log
#next
2.1a 10
2.2a 5
L1.2a (#print
Use the "ls" command to determine if there is a file
named for a state in the current directory.
Find out and type "yes" or "no".
(Don't use the list you got earlier - I've changed things.)
#create texas
dallas, houston, etc.
#copyin
#user
#uncopyin
#match yes
#log
#next
2.1a 10
2.2a 5
L1.2b D #print
You can use the "ls" command to find out how
many files you have in your directory.
How many files are there in the current
directory now? Make another list - the list of files
that you made before is no longer right because I added
some files to the directory. When you find out
how many files there are in this directory, type
"answer N" where N is the number of files.
#create a1
file a1
#create a2
file a2
#create X1
file a1
#copyin
#user
#uncopyin
ls | %s/../lcount >X1
tail -1 .copy >X2
#cmp X1 X2
#log
#next
2.1a 10
2.2a 5
L10.1a V $#print
When you are done with something, you will want to know
how to get rid of the file it is on. The command
for that is "rm" (remove). For example
rm junk
throws away the file named "junk". Once it
is gone, it is really gone - there is no way
to "undo" a remove command. Hence this command
should be used with caution.
In this directory there is one file named
for a baseball player. Remove it.
Then type "ready".
#create kernighan
#create yastrzemski
#user
test ! -r yastrzemski && test -r kernighan
#log
#next
11.1a 10
11.2a 5
11.3a 2
L10.2a Q +#print
The way to get rid of a file you are finished with
is with the "rm" (remove) command. For example,
rm junk
will get rid of the file named "junk".
In this directory there is a file named "harry" -
remove it.
Then type "ready".
#create harry
#user
test ! -r harry
#log
#next
10.2b 5
10.3a 2
L10.2b u #print
You can remove several files at once with the "rm" command.
And you can use the familiar "*" and "?" characters
to abbreviate several file names. BUT BE CAREFUL -
"rm" is irreversible, and it is all too easy to type something
like "rm *" and get rid of all your files.
In this directory are two files named
"part1" and "part2".
Remove both; then type "ready".
#create part1
#create part2
#user
test ! -r part1 && test ! -r part2
#log
#next
11.1a 10
11.2a 5
11.3a 2
L10.3a P #print
When you are done with something, you will want to
get rid of the file containing it. The command for that
is "rm" (remove). For example
rm junk
throws away the file named "junk". Try that -
there's a file named "junk" in this directory, as you can
verify by doing an "ls". Try another "ls" after the "rm junk";
then type "ready".
#create junk
#user
test ! -r junk
#log
#next
10.3b 2
#L10.3b cP #print
Often you will use "ls" with "rm"
to first find the name of a file, and then remove it.
This directory contains one file whose name begins with "g".
Find out what it is and remove it.
Then type "ready".
#create george
#user
test ! -r george
#log
#next
10.3c 2
L10.3c $P M#print
You can remove several files at once with the
"rm" command; for example,
rm tom dick harry
will remove the files "tom", "dick", and "harry".
There are two files in this directory named
for birds: get rid of both.
Then type "ready".
#create eagle
#create bluejay
#user
test ! -r eagle && test ! -r bluejay
#log
#next
10.3d 2
eL10.3d _ #print
You can also use "*" and "?" with
the "rm" command. BUT BE VERY CAREFUL
since, for example, "rm *" will throw away
ALL the files in a directory.
In this directory are some files named
chunk1, chunk2, chunk3 and chunk4.
Get rid of them. Then type "ready".
#create X1
#
ls >X2
#create chunk1
#create chunk2
#create chunk3
#create chunk4
#user
ls >X1
#cmp X1 X2
#log
#next
11.1a 10
11.2a 5
11.3a 2
L11.1a #print
To create a second copy of a file, the easiest
way is to use the "cp" (copy) command.
If you tell the computer
cp x y
a copy of file "x" is made and named "y".
Note that this is similar to "mv" in that a new
file named "y" appears, but the difference is
that the old file is not removed.
(If there was already a file named "y", though, the
old contents are lost; be careful.)
In this directory there is a file which has
a five letter name whose first four letters
are "part".
Print it out; it will tell you to copy
it and what to call the copy.
Do that and then type "ready".
#create X1
#create george
#create part00
this is not the right file and you shouldn't
have printed it. Use
part?
not
part*
in this example.
#create part3
This is the file "part3". I hope you
used a command like
ls part?
or
cat part?
to find it.
Make a copy of this file on file "george".
#user
#cmp george part3
#log
#next
12.1a 10
12.2a 5
12.3a 2
L11.2a _ =#print
To make a new copy of a file, the easiest
way is to use the "cp" command.
If you type
cp x y
a copy of file "x" is made and named "y".
This directory contains a file named "george";
make a copy named "steve".
Then type "ready".
#create george
this is file george
#user
#cmp steve george
#log
#next
11.2b 5
L11.2b % #print
Contrast
cp old new
with
mv old new
as commands; both cause "new" to appear,
but "cp" does not remove "old".
Both, by the way, destroy anything
that happened to be around named "new".
There is a file in this directory
whose name ends in "x". Use "ls"
with the "*x" construction to find its name;
then copy it to file "new", and type "ready".
#create new
old new
#create pix
new new
#create xip
nothing
#user
#cmp pix new
#log
#next
12.1a 10
12.2a 5
12.3a 2
tL11.3a , #print
To make a copy of a file, you can use the
"cp" (copy) command. For example
cp old new
will make a copy of file "old", named "new".
This directory contains a file named "old";
try the "cp" command to make a file named "new".
Print the file to check on the copy.
When done, type "ready".
#create old
The Brooklyn Museum is at 188 Eastern Parkway,
Brooklyn, NY 11238.
#user
#cmp old new
#log
#next
11.3b 2
L11.3b 4 #print
Now there is a file named "good"
in this directory. Make a copy named "better",
then type ready.
#create good
This file has
three lines
in it.
#user
#cmp good better
#log
#next
11.3c 2
L11.3c : #print
This is a little trickier. The directions
for this step are in a file whose
name begins with "p". Print that file;
it will tell you what to do. Then type "ready".
#create delaware
narrowsburg
port jervis
delaware water gap
easton
trenton
philadelphia
#create pub
Make a copy of the file "delaware" which is
named "hudson".
#user
#cmp delaware hudson
#log
#next
12.1a 10
12.2a 5
12.3a 2
L12.1a _ #print
Another very useful command is the command
diff x y
which compares two files. It will not print
any output if the two files are the same, but
if the files are different it will print
out the lines that are changed in the two files,
indicating the lines from the first file (x) by a leading "<"
and the lines from the second file (y) by a leading ">".
There are two files in this directory named "old" and "new".
Why don't you first print both files, and then
try using "diff" to compare them? Suppose the files
were hundreds of lines long, and you needed to know
the single difference - do you see how valuable "diff" can be?
As evidence that you did at least half of this,
type "answer word" where "word" is the word added to the
second file.
#create new
Four score and seven
years ago our fathers
brought forth on this
continent a new nation,
conceived in liberty
and dedicated to the
proposition that all
men are created equal.
#create old
Four score and seven
years ago our fathers
brought forth on this
continent a new nation,
conceived in liberty
and dedicated the
proposition that all
men are created equal.
#copyin
#user
#uncopyin
#match to
#log
#next
13.1a
L12.2a _ *#print
To compare two files, you can use the command
"diff" (differences); the line
diff xx yy
will compare the files xx and yy and tell you about
any differences between them. If the files are the same,
the command says nothing. Are the files
"tom" and "dick" the same in this directory?
Find out (print them if you feel insecure)
and reply "yes" or "no".
#create dick
This stuff is not only in
file tom but also
in file dick
#create tom
This stuff is not only in
file tom but also
in file dick
#copyin
#user
#uncopyin
#match yes
#log
#next
12.2b 5
L12.2b @ #print
Now are the files "dick" and "harry" the same?
Again reply "yes" or "no".
If there are differences between files, "diff" prints
the lines that are different, indicating those
from the first file by "<" and those from
the second file by ">".
#create dick
new york
bridgeport
new haven
new london
providence
boston
#create harry
new york
bridgeport
new haven
providence
boston
#copyin
#user
#uncopyin
#match no
#log
#next
12.2c 5
aL12.2c @A M#print
This directory contains two files named "old" and "new";
What word is in one file but not the other? Find
out. Reply "answer WORD" where WORD is that word.
#create new
Four score and seven
years ago our fathers
brought forth on this
continent a new nation,
conceived in liberty
and dedicated to the
proposition that all
men are created equal.
#create old
Four score and seven
years ago our fathers
brought forth on this
continent a new nation,
conceived in liberty
and dedicated the
proposition that all
men are created equal.
#copyin
#user
#uncopyin
#match to
#log
#next
13.1a
iL12.3a W #print
A very useful command is the command
diff x y
which compares the two files x and y and tells
you any differences between the files. If the files
are the same, it says nothing. To test that,
copy file "george" onto file "harry";
then say
diff george harry
to verify that the files are the same.
#create george
london bridge
is falling down.
#copyin
#user
#uncopyin
#match diff george harry
#match diff harry george
#log
#next
12.3b 2
L12.3b &_ l#print
Are the files "memo1" and "memo2" the same?
If they are different, "diff" will print the
lines that are not the same.
Reply "yes" or "no".
#create memo1
A quick brown fox jumps over the lazy dog.
We were away a year ago.
#create memo2
A quick brown fox jumps over the lazy dog.
We were away a year ago.
#copyin
#user
#uncopyin
#match yes
#log
#next
12.3c 2
L12.3c )_ #print
Are the files "old" and "new" in this directory the same?
Again, if they are not, "diff" will print out the differences
marking the lines in the first file named by "<" and the
lines in the second file by ">". Check the results of
diff by printing the files. Then type "yes" or "no".
#create new
This file has three
lines of text in
it to read.
and this has one more.
#create old
This file has three
lines of text in
it to read.
#copyin
#user
#uncopyin
#match no
#log
#next
12.2c 5
eL13.1a D 2#print
Let's do a quick review of the things covered
in the files course. To begin, how many files
are there in the current directory? Type "answer N",
where N is the number that you found.
#create X1
#create X2
#copyin
#user
#uncopyin
ls | %s/../lcount >X1
tail -1 .copy >X2
#cmp X1 X2
#log
#next
13.1b 5
L13.1b UA #print
There is a file in this directory whose name begins
with 'z'. Do what it tells you to, then type "ready".
#create X1
#create X2
#create zip
Rename the file named "mary" to "joe".
#create joe
I am a file
#
rm -f mary
ls >X1
mv joe mary
#user
ls >X2
#cmp X1 X2
#log
#next
13.1c 5
2L13.1c `{ /#print
There are two files in this directory whose names begin with
the letter 'r'. On what line do they differ?
Type "answer N", where N is the line number where they
first are different.
#create ref
This is a very short file
which contains several lines
some one of which will be changed
in the other version, and your
job is to find out which.
#create refnew
This is a very short file
which contains several lines
some one of which will be changed
in the other version, and your
job is to find out which.
#copyin
#user
#uncopyin
#match 3
#log
#next
13.1d
oL13.1d 5_ #print
There are several files in this directory whose names
begin with "easy". Remove them, then type "ready".
#create X1
#create X2
#
ls >X2
#create easy1
#create easyer
#create easyrider
#create easyenough
#user
ls >X1
#cmp X1 X2
#log
#next
13.1e
L13.1e 8_ #print
This one is tougher than the last one. There are
several files in this directory whose names
begin with "hard". Remove them, then type "ready".
#create X1
#create X2
#
ls >X2
cp X1 "hard 1"
cp X1 "hard er"
#user
ls >X1
#cmp X1 X2
#log
#next
13.1f
L13.1f :_ #print
Suppose you have two files named "dick" and "jane", and you
want to interchange them, so that "dick" contains whatever
was originally in "jane", and "jane" contains what was in "dick".
Will this sequence of commands do the job?
mv dick jane
mv jane dick
There are two files named "john" and "mary"
in this directory, if you wish to experiment.
When you have decided, type yes or no.
#create john
this is originally file john
#create mary
this is originally file mary
#copyin
#user
#uncopyin
#match no
#log
#next
13.1g
yL13.1g =_ #print
Suppose that we really do want to interchange the contents
of the files "dick" and "jane". One way to do it is
to move the contents of "dick" into some temporary file,
then move "jane" onto "dick" (which of course clobbers
the old contents of "dick", but we saved them already),
then finally to move the temporary copy of "dick" to
"jane". There are two files named "dick" and "jane" in this
directory. Interchange their contents, then type "ready".
#create Ref
short file for dick
#create dick
short file for dick
#create jane
another file for jane
#create Ref1
another file for jane
#user
cmp -s jane Ref && cmp -s dick Ref1
#log
hL2.1a ݅ #print
The "mv" command changes the names of files.
For example, "mv bob bill" changes the name
of file "bob" to be "bill". If there was already
a file named "bill", the old version is destroyed.
There is a file in
the current directory whose name begins with
the letter "g", like "grant" or "grover".
Find out what the file name really is, and
then change that file to have the name "john".
Then type "ready".
#create george
this should become john
#user
test -r john
#log
#next
3.1a 10
3.2a 5
3.3a 2
L2.2a #print
The "mv" command changes the names of files.
For example, "mv thomas james" changes the
name of the file "thomas" to be "james".
There is a file in the current directory named
"thomas". Change that file to have the
name "james". Then type "ready".
(The "mv" command, by the way, is like many
UNIX commands in that it is silent unless there is an error.)
#create thomas
xx
#user
test -r james
#log
#next
2.2b 5
L2.2b ĩ ]#print
Now your directory contains a file with a name
that starts with "a" (like "adam", "arthur", etc.).
Find it and change its name to "martin".
Then type "ready".
By the way, if there was already a file around
named "martin", the old version is clobbered
by the new one.
#create andrew
stuff
#user
test -r martin
#fail
Do you remember that the "ls" command will
tell you the names of the files in the current
directory? Thus you can use "ls" to tell you
what your file names are; and then you can use
"mv" to change the name of the file
beginning with "a" to "martin".
#log
#next
3.1a 10
3.2a 5
3.3a 2
hL3.1a dz #print
The "cat" command prints the contents of one or more files.
In fact, it is named "cat" as an abbreviation
for "concatenate". To print the files named "dog"
and "mouse" in succession, you could type either
cat dog
cat mouse
or just
cat dog mouse
If you print them with one command,
the contents are printed in sequence with nothing
between them.
How many lines are there in all the files
whose names begin with "b"? Find out, then type
"answer N" where N is the total number of lines.
#create ben
the file ben has
a total of three
short lines.
#create bernie
this file has
two lines.
#create bruce
only one line here.
#copyin
#user
#uncopyin
#match 6
#log
#next
4.1a 10
4.2a 5
4.3a 2
L3.2a <? h#print
The command "cat" will print files. For example, you
can print the file named "food" by typing "cat food".
Your current directory has a file named "sam" and a
file named "steve". Which is longer? Find out and
type "answer sam" or "answer steve", giving the name
of the longer file.
#create sam
this is the file sam. it contains
only two lines of text.
#create steve
this file is named steve. it is a
file which contains five lines of text.
this is of course a very short file
by any ordinary standards, although
on UNIX most files are rather short.
#copyin
#user
#uncopyin
#match steve
#log
#next
3.2b 5
L3.2b #print
The "cat" command can also print several files
at once. In fact, it is named "cat" as an abbreviation
for "concatenate". To print the files named "dog"
and "mouse" in succession, you could either
type:
cat dog
cat mouse
or just
cat dog mouse
If you print them with one command,
the files are listed in sequence with nothing
between them.
This directory contains two files
named "chester" and "charley". What is the
longest word in either file? Type "answer WORD"
where WORD is the longest word you find.
#create charley
most of this file is short but at one place
there is a surprisingly long word.
#create chester
and of the but here now stop go
#copyin
#user
#uncopyin
#match surprisingly
#log
#next
4.1a 10
4.2a 5
4.3a 2
uL3.3a h#print
A file can be printed on your terminal
by using the "cat" command. Just say
"cat file" where "file" is the file name.
For example, there is a file named
"food" in this directory. List it
by saying "cat food"; then type "ready".
#create food
this is the file
named food.
#copyout
#user
#uncopyout
tail -2 .ocopy >X1
#cmp X1 food
#log
#next
3.3b 2
L3.3b v ##print
Of course, you can print any file with "cat".
In particular, it is common to first use
"ls" to find the name of a file and then "cat"
to print it. Note the difference between
"ls", which tells you the name of the files,
and "cat", which tells you the contents.
One file in the current directory is named for
a President. Print the file, then type "ready".
#create roosevelt
this file is named roosevelt
and contains three lines of
text.
#copyout
#user
#uncopyout
cp .ocopy X2
tail -3 .ocopy >X1
#cmp X1 roosevelt
#log
#next
3.2b 2
L4.1a - _#print
The "ls" command may be given with one
or more file names. In that case,
it will tell which which of the files exist.
How many of the files "doug", "dave", and
"dennis" exist in this directory? Find out
and then type "answer N" where N is the number
you found.
#create dennis
#create doug
#copyin
#user
#uncopyin
#match 2
#log
#next
5.1a 10
L4.2a 7 #print
If a file name is given with the "ls" command,
it tells you whether that file exists.
The file name is listed if the file exists;
if it doesn't, a complaint is typed.
For example,
ls george
will type "george" if the file exists,
and "george not found" if it is missing.
Is there a file named "alexander" in the
current directory? Find out, then type "yes" or "no".
#copyin
#user
#uncopyin
#match no
#log
#next
4.2b 10
L4.2b #print
You can inquire about several files at once
with the "ls" command. If you type, for example,
ls fee fi fo fum
you will be told which of the four files "fee", "fi", "fo",
and "fum" exist. In the current directory only one
of the files "grover", "gerald", or "george" exists.
Find out which one; then rename it "grant".
Type "ready" when you are done.
#create gerald
file
#create garbage
garbage it is.
#user
#create X1
file
#
cmp -s X1 grant && test ! -r gerald
#log
#next
5.1a 10
aL4.3a x H#print
You can use the "ls" command to ask whether
a single file exists without listing the entire
directory. For example, "ls george" will list
"george" if there is a file with that name, and
complain if there is not one. This directory
contains a file named "arthur" but no file named
"alan". You can verify that by typing the
ordinary "ls" command. Then try typing "ls arthur"
to see what happens, and follow that by "ls alan".
Then type "ready".
#create arthur
xxx
#copyin
#user
#uncopyin
grep 'ls arthur' .copy >/dev/null && grep 'ls alan' .copy >/dev/null
#log
#next
4.3b 0
L4.3b g#print
With the "ls" command, you can inquire about several
specific files at once. For example, in the previous
case, you could type
ls arthur alan
and be told about both files.
Which one of the files "bruce" and "ben" exists?
Type "answer NAME", where NAME is the one you find.
#create bruce
bruce
#copyin
#user
#uncopyin
#match bruce
#log
#next
4.3c 2
nL4.3c #print
Your directory contains only one of the following
files: "richard", "robert", "ralph", "roger". Find out
which one exists, and print the contents of that file
on your terminal (remember the "cat" command?).
Then type "ready".
#create robert
this is the contents of file
robert which you had to print.
#copyin
#user
#uncopyin
grep 'cat rob' .copy >/dev/null
#log
#next
5.1a 10
oL5.1a
#print
Most UNIX commands, like "ls" and "cat", let you
specify any number of file names after the command.
To make this as easy as possible, there are some
ways to abbreviate file names. This is usually
faster and more accurate than typing out the list in full.
For example, when the character "?" is used in a file name,
it will represent any character that might be
in a file name. That is, the name "a?" is
an abbreviation for the files "a1", "a2", "aa",
and so forth. You can say
ls a?
and if there are any file names beginning with
"a" that are exactly two letters long, the computer
will tell you their names. Try that here.
First list all the file names with "ls"; then type
ls a?
to get all the two letter names beginning with "a".
Then type "ready".
#create a1
#create a12
#create abcdef
#create ax
#create aa
#copyin
#user
#uncopyin
grep '^ls a?$' .copy >/dev/null
#log
#next
5.1b 0
5.1c 5
5.1e 10
L5.1b m_ k#print
Will the name
xyz
be selected by the pattern
x?
in an "ls" command?
Type "yes" or "no". If you
have trouble, there is such a file
in the current directory,
so you can find out by trial and error.
(For example, you might do an ordinary "ls"
and then try "ls x?" and compare the results.)
#create xyz
#copyin
#user
#uncopyin
#match no
#log
#next
5.1c 0
/L5.1c #print
The "?" may appear anywhere in the name.
For example you can type
a?bc
to match the list of names
axbc, aybc, a3bc
and so forth.
But the number of characters must always agree.
How many of the following file names
are matched by "x?xx"?
x1xx, y1xx, x1xxa, xxx
Type "answer N" where N is the number of matching names.
You can experiment in the current directory to
check your answer before typing it.
#create x1xx
#create x1xxa
#create y1xx
#create xxx
#copyin
#user
#uncopyin
#match 1
#log
#next
5.1d 0
5.1e 5
"L5.1d r_ #print
Will the name
?xx
match "axx"? Again, you may
experiment before typing your
answer.
#create axx
#copyin
#user
#uncopyin
#match yes
#log
#next
5.1e 0
hL5.1e #print
Not only may the ? appear anywhere in a name,
but there may be several ? characters in it.
For example,
g??rge
will match "george" and "goerge", among others.
And "a??" will match "abc" or "a11" (but NOT "ax").
Look at the files in the current directory and decide
how many names the pattern
a?b?c
will select. Again, you can try this out
by comparing an ordinary "ls" with "ls a?b?c"
to see what happens. When you figure
out how many names are selected,
type "answer N" where N is the number of file names.
#create a0b0c
#create a0bc
#create a0x0c
#create a1bxc
#create aabbc
#create azbzcz
#copyin
#user
#uncopyin
#match 3
#log
#next
6.1a 5
6.2a 2
L6.1a h k#print
Since the "?" character only matches single characters,
it isn't useful for such questions as "how many files
have names beginning with g?" There is another character,
*
which can be used in patterns for file names, and which matches
any number of characters of any sort. Thus
g*
matches anything beginning with g.
And
*x
matches anything ending in x.
There is one file in this directory whose name ends
in "memo". Find out that file name
and print the contents of the file. Then type "ready".
#create mymemo
This is the 7-line file "mymemo"; you should
have typed "ls *memo", which would print
"mymemo", and then typed the
command "cat mymemo".
Or just plain "cat *memo" would have worked.
But whatever you did, you got it right
and now you can type "ready".
#copyout
#user
#uncopyout
tail -7 .ocopy >X2
#cmp mymemo X2
#log
#next
6.1b 0
6.1c 5
6.1e 10
iL6.1b ~_ #print
Will the file name "abcd"
be matched by "a*d"? Again,
if you are not sure, you can experiment
in this directory with commands like
"ls" and "ls a*d".
#create abcd
#copyin
#user
#uncopyin
#match yes
#log
#next
6.1c
L6.1c 2 #print
There is one file in this directory whose name begins
with "g". Rename it so the "g" at the beginning
of the name is replaced by "h".
Then type ready.
#create g23
g23, of course
#user
test -r h23 && test ! -r g23
#log
#next
6.1d 0
6.1e 5
L6.1d @ ##print
What does "*b*" match? Clearly, any file
with a "b" anywhere in its name. Similarly,
how many files in this directory have
"se" somewhere in their name?
Type "answer N" when you figure it out.
#create arise
#create reset
#create set
#copyin
#user
#uncopyin
#match 3
#log
#next
6.1e
yL6.1e t #print
There is exactly one file name which matches both
ab*
and
a?d
in the current directory. What is it?
Type "answer NAME" where NAME is its name.
#create abc
#create abd
#create add
#copyin
#user
#uncopyin
#match abd
#log
#next
7.1a 10
7.2a 5
7.3a 2
L6.2a #print
Since the '?' character only matches single
characters in file names, it is not useful for
questions like "how many files have names which
begin with the letter g?" There is another character
*
which can be used in patterns for file names
and matches any number of any kind of characters.
So
g*
selects all file names beginning with g, and
*x
selects all file names which end in x. Try
ls *x
How many files match?
Compare with an ordinary
ls
if you like. Type "answer N" eventually where
N is the number of files whose names end in "x".
#create abcx
#create abcxdef
#create memox
#create memoy
#create memoz
#create x
#create x53x
#copyin
#user
#uncopyin
#match 4
#log
#next
6.2b 8
6.1a 1
eL6.2b #print
There is one file in this directory whose name ends
in "memo". Find out that file name and print
the contents of the file. Then type "ready".
#create mymemo
This is the 7-line file "mymemo"; you should
have typed "ls *memo", which would print
"mymemo", and then typed the
command "cat mymemo".
Or just plain "cat *memo" would have worked.
But whatever you did, you got it right
and now you can type "ready".
#copyout
#user
#uncopyout
tail -7 .ocopy >X2
#cmp mymemo X2
#log
#next
6.1b 0
6.1c 5
6.1e 10
sL7.1a l#print
Sometimes ? is too flexible, and you
only want to allow a few characters. For example,
you might want to abbreviate
ls memo.ab memo.ac
without picking up "memo.ad", memo.ae", etc.
You can match one of a set of particular characters by
putting them in brackets "[]" in the list you use with "ls".
For example,
[bc]
matches either b or c but no other letters,
so "ls memo.a[bc]" is the abbreviation for
"ls memo.ab memo.ac".
You can have as many characters as needed between [ and ].
Type the "ls" command that recognizes
a1cat
a2cat
a3cat
and no other files. Then type "ready".
#create a1bat
#create a1cat
#create a2cat
#create a3cat
#create a4cat
#create acat
#copyin
#user
#uncopyin
#match ls a[123]cat
#match ls a[1-3]cat
#match ls a1cat a2cat a3cat
You were supposed to use a[123]cat.
Imagine doing it your way with 10 files.
#log
#next
8.1a 10
8.2a 5
L7.2a % #print
Sometimes ? is too flexible, and you
only want to allow a few characters. For example,
you might want to abbreviate
ls memo.ab memo.ac
without picking up "memo.ad", "memo.ae", and so forth.
You can match one of a set of particular characters by
putting them in brackets "[]" in the list you use with "ls".
For example,
[bc]
matches either b or c but no other letters. Thus
ls memo.a[bc]
will list exactly "memo.ab" and "memo.ac" if present.
How many of the files
xya, xyb, xyc, xyd
exist in this directory?
Type "answer N" where N is the number.
#create xyb
#create xyc
#create xye
#create xyf
#create xy1
#copyin
#user
#uncopyin
#match 2
#log
#next
7.2b 10
mL7.2b - #print
You can put any number of characters between [..]
characters, as in
[abcdef]
which matches any of the six letters from a to f;
and you can put something like that anywhere in a pattern
for a file name. For example,
ls [abcd]x
matches any of
ax, bx, cx, dx
You can also combine this with other operators such as
* or ?. For example,
ls [ab]?
matches all two-letter names beginning with a or b.
How would you ask for all names, of any length, ending
in 1 2 or 3?
You can experiment in this directory; eventually,
type the "ls" command you decide on followed by "ready".
#create a1
#create a12
#create a1a
#create a2
#create a23
#create aa1
#create abc1
#copyin
#user
#uncopyin
#match ls *[123]
#log
#next
8.1a 10
L7.3a 7 #print
Sometimes ? is too flexible, and you
only want to allow a few characters. For example,
you might want to abbreviate
ls memo.ab memo.ac
without picking up "memo.ad", "!"memo.ae", and so forth.
You can match one of a set of particular characters by
putting them in brackets "[]" in the list you use with "ls".
For example,
[bc]
matches either b or c but no other letters.
Thus the command
ls memo.a[bc]
would match "memo.ab", "memo.ac", and nothing else.
Try that command in this directory: type a plain
"ls" first, and then "ls memo.a[bc]".
How many files does "ls memo.a[bc]" match?
Type "answer N" where N is the number.
#create memo.ab
#create memo.abc
#create memo.bc
#copyin
#user
#uncopyin
#match 1
#log
#next
7.3b 2
sL7.3b î :#print
You can use the [] characters anywhere you want
in a file name. For example,
ls a[bc]d
would match abd or acd, right?
What is the command that finds out how
many files are named "ax" or "bx"?
Type that command, then "ready".
#create ax
#create bx
#copyin
#user
#uncopyin
#match ls [ab]x
#log
#next
7.3c 2
L7.3c #print
You can put any number of characters between the
brackets. For example,
ab[123456789]
could match up to 9 names, of the sort
ab1, ab2, ab3, ab4, ab5, ...
How many of the following names exist in this
directory?
p1end, p2end, p3end, p4end, p5end
Check with a ordinary "ls". Type "answer N" when you
know.
#once #create p1end
#once #create p3endx
#once #create p4end
#once #create p6end
#copyin
#user
#uncopyin
#match 2
#log
#next
8.1a 10
8.2a 5
nL8.1a ޮ #print
Sometimes you want to request one of a limited
range of characters. This is possible with an
expression like
[a-d]
which matches a, b, c, or d. Thus, to take
some combinations
ab[c-f]
matches
abc, abd, abe, abf
Try typing "ls a[0-9]"
and see how many files it matches. Type that
number in the form "answer N".
#create a0
#create a1
#create a5
#create ax
#copyin
#user
#uncopyin
#match 3
#log
#next
9.1a 10
9.2a 4
hL8.2a #print
Will the command
ls georg[a-f]
match the name
george
Type yes or no.
Experiment first if you want.
#create george
#copyin
#user
#uncopyin
#match yes
#log
#next
8.2b 5
9.1a 10
L8.2b _ Z#print
The command
ls [aeiou]*.c
will match all but one of the following names.
e.c
alpha.c
edward
u23.c
Which one? Type "answer NAME" where NAME
is the file that doesn't match. You can experiment
first, as usual.
#create alpha.c
#create e.c
#create edward
#create u23.c
#copyin
#user
#uncopyin
#match edward
#log
#next
8.2c 5
9.1a 10
L8.2c #print
As an example more complicated than you will
probably ever need, consider
?[a-c]*
which matches what? Well the first character
can be anything; the second must be a, b, or c; and
nothing matters thereafter. So it matches
aaa
abc
xa
3c25
but not
a
ghi
and so forth.
Will it match
%a25
Try some experiments, then type yes or no.
#create %a25
#copyin
#user
#uncopyin
#match yes
#log
#next
9.1a 10
9.2a 4
L9.1a (R S#print
The patterns for selecting file names that have been discussed
can be used with other commands than "ls". For example,
they can be used with the "cat" command to print files.
It is common for a memo stored in several
files to use files named "part1", "part2", etc.
so that commands like
cat part*
will print everything.
In this directory there are several
short files named "sec0", "sec1", "sec3",
and so forth.
There are various names of animals in the files;
find out the largest animal named in the files
and type "answer NAME" where NAME is that animal.
#create sec0
dog mouse cat
#create sec1
rabbit weasel
pig hamster
#create sec2
this file doesn't happen
to have any animal names in it.
#create sec3
fox elephant sheep
duck rat
#create sec4
groundhog bobcat
mole beaver
#copyin
#user
#uncopyin
#match elephant
#log
#next
10.1a 10
iL9.2a 6 S#print
You can use patterns for file names with commands
other than "ls". For example, you can use them with
the "cat" command to print files.
This directory has three files named
parta
partb
partc
You can use
cat part?
to print all of them. Try that; then
type "ready".
#create parta
This is file parta;
it has two lines.
#create partb
File partb here - has only one line.
#create partc
And now in file partc, which has
the enormous total of
three lines.
#create partxxx
You shouldn't have printed this one.
#copyin
#user
#uncopyin
grep 'cat part?' .copy >/dev/null
#log
#next
9.2b 5
pL9.2b D #print
You can also use the "*" operator. For example,
print the contents of all the files in this
directory whose names begin with the letter 'p'.
Use just one "cat" command.
Then type "ready".
#create p1
There are only two such files. This is the first
one and it is two lines long.
#create ppx
This is the second file. Its first line
is blank, and then there are three lines of
text of which this is the last.
#copyin
#user
#uncopyin
grep 'cat p\*' .copy >/dev/null
#log
#next
10.1a 10
9.2c 5
L9.2c }= d#print
And as an example of the [] operators again,
print all the files in this directory whose
names begin with either 'a' or 'c'.
That will tell you to type either 'yes'
or 'no' - do what it says.
#create a1
Type
#create a2
y
#create b
n
o
#create cxx
e
#create cz23
s
(on one line, please)
#copyin
#user
#uncopyin
#match yes
#log
#next
10.1a 10
10.3a 2