home | O'Reilly's CD bookshelfs | FreeBSD | Linux | Cisco | Cisco Exam    

UNIX Power Tools

UNIX Power ToolsSearch this book
Previous: 16.16 Picking a Unique Filename Automatically Chapter 16
Where Did I Put That?
Next: 16.18 Listing Files You've Created/Edited Today
 

16.17 Getting Directory Name from a File's Pathname

When you write shell scripts or functions, sometimes you have a file's absolute pathname but need the parent directory's name. (You might need the parent's name to see if you have write permission in the directory - say, to remove or rename the file.)

If the pathname is stored in a csh shell (not environment) variable, use the modifier :h ( 9.6 ) . In the Bourne shell, see if your system has the dirname ( 45.18 ) command. If it doesn't, you can get the GNU version from the Power Tools disc - or use expr ( 45.28 ) with a regular expression ( 26.4 ) that gives you everything up to (but not including) the last slash. For example, if the pathname /home/mktg/fred/afile is stored in the shell variable file , these csh and sh commands would store /home/mktg/fred into the variable dir :

% 

set dir=$file:h


$ 

dir=`dirname "$file"`


$ 

dir=`expr "$file" : '\(.*\)/'`

To handle multiple pathnames, give this regular expression to sed ( 34.24 ) :



@
 

% ... 

sed 's@/[^/]*$@@'

 ...

- JP


Previous: 16.16 Picking a Unique Filename Automatically UNIX Power Tools Next: 16.18 Listing Files You've Created/Edited Today
16.16 Picking a Unique Filename Automatically Book Index 16.18 Listing Files You've Created/Edited Today

The UNIX CD Bookshelf Navigation The UNIX CD BookshelfUNIX Power ToolsUNIX in a NutshellLearning the vi Editorsed & awkLearning the Korn ShellLearning the UNIX Operating System










??????????????@Mail.ru