Sponsored Content
Top Forums UNIX for Advanced & Expert Users How to prevent Accidents 'rm -rf *'? Post 302904226 by Don Cragun on Tuesday 3rd of June 2014 03:03:21 AM
Old 06-03-2014
Quote:
Originally Posted by cero
One way would be alias rm to a script that checks its parameters:
Code:
alias rm='/usr/local/bin/myrm.sh

Code:
#!/bin/bash
# script: myrm.sh
# check parameters to prevent system damage

[ "$*" = "-rf $(echo /*)" ] && echo "Illegal parameters" && exit 1

/bin/rm $@

This is an extremely dangerous script. It seems to be intended to catch an attempt to remove all files in and under the root directory. But,it won't complain if you try any of the following (all of which do exactly what this script seems to be intended to catch):
Code:
rm -r -f /*
rm -f -r /*
rm -fr /*
cd /; rm -rf *
rm -rf /

It won't complain if there happen to be any files in the root directory that contain a tab character, start or end with a space character, or contain two or more adjacent space characters. It will fail if any file is added to or removed from the root directory between the time when the rm alias was called and the time when this script processes echo. And, it will attempt to remove a different set of files than what was requested if any files in the operand list contain any whitespace characters.
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

Prevent bash from interpretation :

I am using bash shell; my requirement is to run a long command. Now I have split this long command into a number of shell variables. Some of these shell variables contain special character ':' At the end, when the intended long command is executed as a series of small shell variables the ':'... (7 Replies)
Discussion started by: uday
7 Replies

2. UNIX for Dummies Questions & Answers

Prevent history entry

Is there anyway to prevent a command from being logged in the history file? I share a system with others (log in with same account) and I would like to prevent any passwords from being logged in the history file. Some of the commands that I run require username/password on the command line... (7 Replies)
Discussion started by: here2learn
7 Replies

3. Programming

how to prevent deadlock on this...

I am using linux termios structure to configure serial port and read the port by read function. For some reason, if I read the whole buffer, almost every time the buffer does not contain the correct reply message sequence from a device sending reply to my linux PC. So I use... (5 Replies)
Discussion started by: yimab
5 Replies

4. Shell Programming and Scripting

Prevent output to window

hello, Any suggestion on how to prevent Standard output and Standard Error to window? (3 Replies)
Discussion started by: katrvu
3 Replies

5. Programming

How to prevent a class from inheretance?

:(Hi, There is a class in C++ called "CL". It should not participate in inheretance. If some body inherit it it should give errors.....:( (0 Replies)
Discussion started by: krishna_sicsr
0 Replies

6. UNIX for Advanced & Expert Users

Parallel access - how to prevent

I have one shell script which is being accessed by many jobs at same time. I want to make the script such that , other job should wait for the script if script is being used by some other job. Is there any way to implement it in script level ? Gops (1 Reply)
Discussion started by: Gopal_Engg
1 Replies

7. UNIX for Dummies Questions & Answers

How to prevent queues from disabling themselves

I understand that on my HP-UX 11.31 system when print queues can no longer communicate with remote printers, the queue disables itself. How can I configure it to stop disabling itself, or alternatively, to re-enable itself when the remote printer comes back online? I have users in warehouses who... (6 Replies)
Discussion started by: EatenByAGrue
6 Replies

8. Shell Programming and Scripting

how to prevent process from being killed

Hi,all.Well,I know someone has already asked this question before,however,It's too long before.So i post a new thread here. Here is the issue.I have a shell script that use awk to calculate something and the script takes about 15 mins,it will use 100% CPU,and the system automatically killed the... (2 Replies)
Discussion started by: homeboy
2 Replies

9. Shell Programming and Scripting

How to prevent command from deleted

Hi, I've been searching around for solution, hope that some gurus here can help. I'm using some commands in my shell script and I'd like to protect these command to be moved to another directory. For instance, cp currently in /bin/cp. If I move it to /bin/cpxxx, my script will not be able to... (3 Replies)
Discussion started by: gklntn
3 Replies

10. Emergency UNIX and Linux Support

How to prevent emails as spam?

If an email is sent from our application server(running on AIX) to an id that is outside of the organization like gmail etc, and if gmail should not treat the mail as spam, what has to be done from unix level? (7 Replies)
Discussion started by: ggayathri
7 Replies
WHICH(1)						      General Commands Manual							  WHICH(1)

NAME
which - shows the full path of (shell) commands. SYNOPSIS
which [options] [--] programname [...] DESCRIPTION
Which takes one or more arguments. For each of its arguments it prints to stdout the full path of the executables that would have been exe- cuted when this argument had been entered at the shell prompt. It does this by searching for an executable or script in the directories listed in the environment variable PATH using the same algorithm as bash(1). This man page is generated from the file which.texinfo. OPTIONS
--all, -a Print all matching executables in PATH, not just the first. --read-alias, -i Read aliases from stdin, reporting matching ones on stdout. This is useful in combination with using an alias for which itself. For example alias which='alias | which -i'. --skip-alias Ignore option `--read-alias', if any. This is useful to explicity search for normal binaries, while using the `--read-alias' option in an alias or function for which. --read-functions Read shell function definitions from stdin, reporting matching ones on stdout. This is useful in combination with using a shell func- tion for which itself. For example: which() { declare -f | which --read-functions $@ } export -f which --skip-functions Ignore option `--read-functions', if any. This is useful to explicity search for normal binaries, while using the `--read-functions' option in an alias or function for which. --skip-dot Skip directories in PATH that start with a dot. --skip-tilde Skip directories in PATH that start with a tilde and executables which reside in the HOME directory. --show-dot If a directory in PATH starts with a dot and a matching executable was found for that path, then print "./programname" rather than the full path. --show-tilde Output a tilde when a directory matches the HOME directory. This option is ignored when which is invoked as root. --tty-only Stop processing options on the right if not on tty. --version,-v,-V Print version information on standard output then exit successfully. --help Print usage information on standard output then exit successfully. RETURN VALUE
Which returns the number of failed arguments, or -1 when no `programname' was given. EXAMPLE
The recommended way to use this utility is by adding an alias (C shell) or shell function (Bourne shell) for which like the following: [ba]sh: which () { (alias; declare -f) | /usr/bin/which --tty-only --read-alias --read-functions --show-tilde --show-dot $@ } export -f which [t]csh: alias which 'alias | /usr/bin/which --tty-only --read-alias --show-dot --show-tilde' This will print the readable ~/ and ./ when starting which from your prompt, while still printing the full path when used from a script: > which q2 ~/bin/q2 > echo `which q2` /home/carlo/bin/q2 BUGS
The HOME directory is determined by looking for the HOME environment variable, which aborts when this variable doesn't exist. Which will consider two equivalent directories to be different when one of them contains a path with a symbolic link. AUTHOR
Carlo Wood <carlo@gnu.org> SEE ALSO
bash(1) WHICH(1)
All times are GMT -4. The time now is 02:58 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy