strfile
reads a file containing groups of lines separated by a line containing
a single percent `%' sign (or other specified delimiter character) and
creates a data file which contains a header structure and a table of
file offsets for each group of lines. This allows random access of the
strings.
The output file, if not specified on the command line, is named
sourcefile.dat.
The purpose of
unstr
is to undo the work of
strfile.
It prints out the strings contained in the sourcefile, which is
datafile.ext
without its extension, or
datafile
if no extension is specified (in this case, the extension
.dat
is added to the name of the datafile) in the order
that they are listed in the header file
datafile.
If no
outputfile
is specified, it prints to standard output; otherwise it prints
to the file specified.
unstr
can also universally change the delimiter character in a strings file.
It is possible to create sorted versions of input files by using
strfile -o
and then using
unstr
to dump them out in the table order.
Options
The options are as follows:
-c char
Change the delimiting character from the percent sign to
char.
This option is available for both
strfile and unstr.
-i
Ignore case when ordering the strings.
-o
Order the strings in alphabetical order. The offset table will be
sorted in the alphabetical order of the groups of lines referenced.
Any initial non-alphanumeric characters are ignored. This option
causes the STR_ORDERED bit in the header
str_flags
field to be set. (It also now really does sort! It didn't used to).
-r
Randomize access to the strings. Entries in the offset table will be
randomly ordered. This option causes the STR_RANDOM bit in the header
str_flags
field to be set. (And really does randomize)
-s
Run silently; don't give a summary message when finished.
-x
Note that each alphabetic character in the groups of lines is rotated
13 positions in a simple caesar cypher. This option causes the
STR_ROTATED bit in the header
str_flags
field to be set. Note that it
does not
rotate the strings--that operation must be performed separately.
Header
The format of the header is:
#define VERSION 1
unsigned long str_version; /* version number */
unsigned long str_numstr; /* # of strings in the file */
unsigned long str_longlen; /* length of longest string */
unsigned long str_shortlen; /* shortest string length */
#define STR_RANDOM 0x1 /* randomized pointers */
#define STR_ORDERED 0x2 /* ordered pointers */
#define STR_ROTATED 0x4 /* rot-13'd text */
unsigned long str_flags; /* bit field for flags */
char str_delim; /* delimiting character */
All fields are written in network byte order.
BUGS
Fewer now, one hopes. However, fortunes (text strings) beginning with a
blank line appear to be sorted between random letters. This includes
ASCII art that contains no letters, and first lines that are solely
non-alphanumeric, apparently. I've no idea why this should be.
OTHER USES
What can you do with this besides printing sarcastic and obscene messages
to the screens of lusers at login or logout?
There
are
some other possibilities. Source code for a sample program,
randstr,
is included with this distribution: randstr splits the difference between
unstr and fortune.
It reads a single, specified file, and randomly selects a single text
string.
1
Include
strfile.h
into a news reading/posting program, to generate random signatures.
Tin(1)
does something similar, in a much more complex manner.
2
Include it in a game. While strfile doesn't support 'fields' or
'records', there's no reason that the text strings can't be consistent:
first line, a die roll; second line, a score; third and subsequent lines,
a text message.
3
Use it to store your address book. Hell, some of the guys I know
would be as well off using it to decide who to call on Friday nights (and
for some, it wouldn't matter whether there were phone numbers in it or not).
4
Use it in 'lottery' situations. If you're an ISP, write a script to
store login names and GECOS from
/etc/passwd
in strfile format, write another to send 'congratulations, you've won'
to the lucky login selected. The prize might be a month's free service,
or if you're AOL, a month free on a real service provider.
The
strfile
utility first appeared in 4.4BSD. This version was heavily modified,
much of it in ways peculiar to Linux. Work has since been done to make
the code more generic, and has so far been tested to work with SunOS
4.x. More platforms are expected to be supported as work continues.
