Important note

These pages are deprecated (latest changes date from end 2001). More recent information may be found at http://www.coresequence.com/training.php. I leave the old pages here as they are because lots of people are still visiting them (eventhough they aren't spell-checked), and because the basics are still useful.

Managing Files

In this chapter we will discuss files: filenames, how you can move files about, copy, link and delete them. We will briefly discuss printing, from the point of view of the user.

Names

As we discussed earlier, a directory is just a special file, so all naming rules for files apply equally to directories.

File names may contain any character except a /, which is reserved by the system as a separator between files and directories in a pathname. Even spaces are legal in a filename, but they can be hard to spot. Other special characters are allowed as well, but we advice on using only letters, numbers and dots, because the shell has its own interpretation for special characters.

Some legal filenames

  • chap1 and 2chap

  • a.very.long.filename.for.a.very.short.file

  • another-long-filename

Note

Unix filenames do not, unlike some other systems, require a dot in the name.

Note

On some older systems, the lenght of the filename may be limited to 14 characters. On most modern Unices it is also limited, but within reason.

Note

A filename must be unique in its directory. Note that file, File, fILE and FILE are 4 different files (Unix is case-sensitive).

Wildcards

Wildcards are used to specify a requirement to which filenames should comply. We'll show a practical example using the ls and cd command.


tille:~/files>ls
a304.htm   abook.ps   book1.htm  c174.htm  c69.htm    chap3.xml  php-man
abook.aux  abook.tex  c128.htm   c18.htm   c70.htm    chap4.xml  test/
abook.dvi  abook.xml  c129.htm   c255.htm  chap1.xml  f13.htm
abook.log  app1.xml   c17.htm    c304.htm  chap2.xml  f14.htm

tille:~/files>ls c*
c128.htm  c17.htm   c18.htm   c304.htm  c70.htm    chap2.xml  chap4.xml
c129.htm  c174.htm  c255.htm  c69.htm   chap1.xml  chap3.xml

tille:~/files>ls chap*
chap1.xml  chap2.xml  chap3.xml  chap4.xml

tille:~/files>ls ?h*
chap1.xml  chap2.xml  chap3.xml  chap4.xml  php-man

tille:~/files>ls chap[1-4].xml
chap1.xml  chap2.xml  chap3.xml  chap4.xml

tille:~/files>cd t*

tille:~/files/test>

The asterix will replace as many characters as possible, while the question mark only replaces a single character. Square brackets match a series of characters, as shown in the example below, which prints all programs in /bin starting with a, b or c:


tille@sprawl:~>ls /bin/[a-c]*
/bin/arch*          /bin/awk@      /bin/bsh@   /bin/chown*        /bin/csh@
/bin/ash*           /bin/basename* /bin/cat*   /bin/consolechars* /bin/cut*
/bin/ash.static*    /bin/bash*     /bin/chgrp* /bin/cp*
/bin/aumix-minimal* /bin/bash2@    /bin/chmod* /bin/cpio*