Linux System Administration

bash Beginnings

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To make changes such as this one stick, you’ll need to make a permanent change to

your

PATH. This can be done by an individual user in the .bashrc file located in the

user’s home directory, or by the system administrator in a system-wide startup file

(usually located in the /etc directory); just add a statement to the file like the com-

mand just shown.

Alternatively, you could move the hello script to one of the directories already in the

PATH. However, these directories are usually protected so that only the root user can

put files there, to preserve security.

For a script more complex than hello (i.e., almost any script), either method has

security implications. If

. is in your PATH, you run the risk that if someone else puts a

different script named hello in another directory and you blunder into that directory

and type hello, you’ll execute the other user’s hello and not the one you intended.

The correctness of the script is also a concern. We’re reasonably sure about what our

hello script does now, but we might not be after adding a hundred more lines.

A common practice is to put your own scripts in a directory like /usr/local/bin or a pri-

vate ~/bin rather than a system directory like /bin, /sbin,or/usr/bin. To add this direc-

tory to your

PATH permanently, add a line like the following at the end of your .bashrc

file:

export PATH=$PATH:/usr/local/bin

I/O Redirection

I/O