Pathname Expansion

Many utilities supplied with gsh take, as an argument, a filename or filenames. The shell utilities cat, ls, grep, and cp can take multiple filenames as arguments. If you wish to invoke any of these utilities on filenames that have a sequence of characters in common (ie. AND, APPLE, SHK, TXT, FILE2, FILE3, etc), gsh provides special characters, called regular expressions or wildcards, which match multiple filenames without having to enter all filename arguments manually.

Table 2. GSH Wildcard Operators

*Matches any string of characters.
?Matches a single character.
[abc]Matches any of the characters enclosed in brackets.
[^abc]Matches any of the characters not enclosed in brackets.
[a-c]Matches the ascending sequence of characters enclosed in brackets.

This method of matching filenames is known as "globbing". gsh performs globbing on the word prior to executing the command. The following gsh session illustrates file globbing:


[1]% cd /dev/gno/utilities
[2]% ls
:dev:gno:utilities
CONV      Crunch    CrunchIIGS DeRez      DiskCheck
DumpObj   Duplicate EMACS      Equal      Express
Files     LinkIIGS  MakeBin    MakeDirect OrcaDumpIIGS
Prizm     ResEqual  Search     canon      choose
clrff     cmdfix    coff       compact    count
detab     dir       dirff      dumpfile   eject
emacs.doc emacs.hlp emacs.rc   emacs.tut  help
init      join      link       macgen     makelib
mem       online    pageeject  pause      pwd
src 
[3]% ls e*
:dev:gno:utilities
EMACS     Equal     Express    eject      emacs.doc 
emacs.hlp emacs.rc  emacs.tut
[4]% echo *r *m
dir Prizm mem
[5]% echo *i*
cmdfix CrunchIIGS Prizm DiskCheck Duplicate Files init
join LinkIIGS makelib MakeBin MakeDirect link dirff
dumpfile online OrcaDumpIIGS dir
[6]% echo NoMatch*
No match.
[7]% echo [a-f]*
coff canon cmdfix compact Crunch CrunchIIGS DeRez DiskCheck
DumpObj Duplicate EMACS emacs.doc emacs.hlp emacs.rc
emacs.tut Equal Express Files choose clrff count detab CONV
dirff dumpfile eject dir
[8]% echo [a-fs-t]*
coff canon cmdfix compact Crunch CrunchIIGS DeRez DiskCheck
DumpObj Duplicate EMACS emacs.doc emacs.hlp emacs.rc
emacs.tut Equal Express Files choose clrff count detab
Search src CONV dirff dumpfile eject dir
[9]% echo emacs?*
EMACS emacs.doc emacs.hlp emacs.rc emacs.tut
[10]% echo [^a-f]*
Prizm help init join LinkIIGS makelib MakeBin MakeDirect
link mem ResEqual Search src online pageeject pause
OrcaDumpIIGS pwd macgen
[11]% echo [^a-fs-t]*
Prizm help init join LinkIIGS makelib MakeBin MakeDirect
link mem ResEqual online pageeject pause OrcaDumpIIGS pwd
macgen
[12]% echo ???
mem src pwd dir
[13]% echo ?
No match.
[14]% echo "???"
???
[15]% do you have a light?
No match.

As can be seen by the above example, character matches are case insensitive. The ProDOS file system treats the filenames "file" and "FILE" as the same file. gsh recognizes this and does not detract from the underlying file system.

File globbing makes passing arguments to commands much easier and much more powerful. You could easily use "*.c" as an argument in a number of ways:


[1]% ls *.C    lists all filenames ending in ".C"
[2]% cc *.C    compiles all files ending in ".C"
[3]% more *.C  displays contents of all files ending in ".C"