Skip to Main Content
Linux System Administration
book

Linux System Administration

by Tom Adelstein, Bill Lubanovic
March 2007
Intermediate to advanced content levelIntermediate to advanced
304 pages
11h 12m
English
O'Reilly Media, Inc.
Content preview from Linux System Administration
Useful Elements for bash Scripts
|
221
Troubleshooting a Simple Script
Let’s perform some surgery on a script that is supposed to delete its argument (a file
or a directory) but has a few problems:
admin@server1:~$ cat delete
#!/bin/bash
if rm $1
then
echo file $1 deleted
else
if rmdir $1
then
echo directory $1 deleted
fi
fi
The script is intended to delete the file passed as an argument using rm, and to print
a message if it succeeds. If rm fails, the script assumes the argument refers to a direc-
tory and tries rmdir instead.
Here are some results:
admin@server1:~$ ./delete hello2
file hello2 deleted
admin@server1:~$ ./delete hello2
rm: cannot remove `hello2': No such file or directory
rmdir: `hello2': No such file or directory
admin@server1:~$ mkdir hello3
admin@server1:~$ ./delete hello3
rm: cannot remove `hello3': Is a directory
directory hello3 deleted
admin@server1:~
Using these error messages, let’s try to fix the script. First, we’ll use I/O redirection
to save results to log and error files, which we can review in our copious free time.
Next, we’ll catch the return value of the rm command to generate a success or fail-
ure message. We’ll also capture the current date and time to include in the output
log:
admin@server1:~$ cat removefiles
#!/bin/bash
# removefiles deletes either files or directories
echo "$0 ran at" $(date) >> delete.log
if rm $1 2>> delete-err.log
then
echo "deleted file $1" >> delete.log ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Start your free trial

You might also like

Mastering Linux System Administration

Mastering Linux System Administration

Christine Bresnahan, Richard Blum
Mastering Linux Administration

Mastering Linux Administration

Alexandru Calcatinge, Julian Balog

Publisher Resources

ISBN: 9780596009526Supplemental ContentCatalog PageErrata