Unix find tutorial

Prev | Contents | Next

Part 7: Finding World Writable, Abandoned and other Abnormal Files

Often system administrators need to detect "abnormal" files (e.g., world writable files, files with no valid owner and/or group, SetUID files, files with unusual permissions, sizes, names, or dates). We already discusses a very important case of SUID/SGUID files.

Here is several simplified (usually you need to avoid traversing special filesystem and NFS mounts) but potentially useful examples:

• If you want to rename the file with the strange name, following modification to the find command works:

      find . -inum number -ok mv '{}' new_filename \;

• To find all world writable directories:

  find / -perm -0002 -type d -print

• To find all world writable files:

  find / -perm -0002 -type f -print

• Find both files and directories (exclude symbolic links which produce false positives)

  find / -perm -2 ! -type l -ls

• Find files with messed UID or GID (possible as the result untarting files as root on a server with different structure of user accounts and groups):

  find / -nouser -o -nogroup -print

  to fix

  find / -nouser -o -nogroup -print0 | xargs -0 chgrp root:root

• Find broken symbolic links

  $ find / -type l -print | perl -nle '-e || print';

  Note: This command starts at the topmost directory (/) and lists all links (-type l ) that the perl interpreter determines broken links (-nle '-e || print'). You can further pipe the output through xargs and use the rm -f {} if you want to delete such symbolic links.
  

• Clean out core dumps and temporary files

  find . \( -name a.out -o -name '*.o' -o -name 'core' \) -exec rm {} \;

Those examples are pretty simplistic as in "real life" you need to be able to block traversing of NFS and other non-native filesystems and avoid getting to special memory-mapped filesystems like proc. Earlier versions of GNU find were allergic to proc filesystem. Here is one useful approach described in from Wayne Pollock's Unix-Linux find Command Tutorial

As a system administrator you can use find to locate suspicious files (e.g., world writable files, files with no valid owner and/or group, SetUID files, files with unusual permissions, sizes, names, or dates). Here's a final more complex example (which I save as a shell script):

find / -noleaf -wholename '/proc' -prune \
     -o -wholename '/sys' -prune \
     -o -wholename '/dev' -prune \
     -o -wholename '/windows-C-Drive' -prune \
     -o -perm -2 ! -type l  ! -type s \
     ! \( -type d -perm -1000 \) -print

This says to search the whole system, skipping the directories /proc, /sys, /dev, and /windows-C-Drive (presumably a Windows partition on a dual-booted computer). The Gnu -noleaf option tells find not to assume all remaining mounted filesystems are Unix file systems (you might have a mounted CD for instance). The -o is the Boolean OR operator, and ! is the Boolean NOT operator (applies to the following criteria).

Another and potentially simpler and faster approach is to use -fstype type predicate. It is true if the filesystem to which the file belongs is of type type. For example on Solaris mounted local filesystems have type ufs (Solaris 10 added zfs). For AIX local filesystem is jfs or jfs2 (journalled file system).

But sometimes the same server uses several types of local filesystems (for example ext3 ). In this case you can use predicate OR and create expression that covers each used filesystem or use generic predicate local and in certain circumstances predicate mount.

Strange Files Deletion and Renaming in Shell

There may come a time that you will discover that you have somehow created a file with a strange name that cannot be removed through conventional means. This section contains some unconventional approaches that may aid in removing such files.

Files that begin with a dash can be removed by typing

    rm ./-filename

    rm -- -filename

    rm - -filename

    rm -i *

Another method that can be used is to obtain the inode number of the strange file using ls:

    ls -i

    find . -inum number -ok rm '{}' \;

The -ok flag causes a confirmation prompt to be displayed. This is for your safety in case you mistypes inode number.

If you want to rename the file with the strange name, following modification to the find command works:

    find . -inum number -ok mv '{}' new_filename \;

NEWS CONTENTS

Old News ;-)

[Jul 03, 2016] Strange Files Deletion and Renaming in Shell

https://twitter.com/climagic

find . -empty -type d # List of empty subdirectories of current directory.

Recommended Links

Softpanorama Recommended

Top articles

Sites

Top articles

Sites

Strange Files Deletion and Renaming in Shell

Prev | Contents | Next

Etc

Society

Groupthink : Two Party System as Polyarchy : Corruption of Regulators : Bureaucracies : Understanding Micromanagers and Control Freaks : Toxic Managers :   Harvard Mafia : Diplomatic Communication : Surviving a Bad Performance Review : Insufficient Retirement Funds as Immanent Problem of Neoliberal Regime : PseudoScience : Who Rules America : Neoliberalism  : The Iron Law of Oligarchy : Libertarian Philosophy

Quotes

War and Peace : Skeptical Finance : John Kenneth Galbraith :Talleyrand : Oscar Wilde : Otto Von Bismarck : Keynes : George Carlin : Skeptics : Propaganda  : SE quotes : Language Design and Programming Quotes : Random IT-related quotes :  Somerset Maugham : Marcus Aurelius : Kurt Vonnegut : Eric Hoffer : Winston Churchill : Napoleon Bonaparte : Ambrose Bierce :  Bernard Shaw : Mark Twain Quotes

Bulletin:

Vol 25, No.12 (December, 2013) Rational Fools vs. Efficient Crooks The efficient markets hypothesis : Political Skeptic Bulletin, 2013 : Unemployment Bulletin, 2010 :  Vol 23, No.10 (October, 2011) An observation about corporate security departments : Slightly Skeptical Euromaydan Chronicles, June 2014 : Greenspan legacy bulletin, 2008 : Vol 25, No.10 (October, 2013) Cryptolocker Trojan (Win32/Crilock.A) : Vol 25, No.08 (August, 2013) Cloud providers as intelligence collection hubs : Financial Humor Bulletin, 2010 : Inequality Bulletin, 2009 : Financial Humor Bulletin, 2008 : Copyleft Problems Bulletin, 2004 : Financial Humor Bulletin, 2011 : Energy Bulletin, 2010 : Malware Protection Bulletin, 2010 : Vol 26, No.1 (January, 2013) Object-Oriented Cult : Political Skeptic Bulletin, 2011 : Vol 23, No.11 (November, 2011) Softpanorama classification of sysadmin horror stories : Vol 25, No.05 (May, 2013) Corporate bullshit as a communication method  : Vol 25, No.06 (June, 2013) A Note on the Relationship of Brooks Law and Conway Law

History:

Fifty glorious years (1950-2000): the triumph of the US computer engineering : Donald Knuth : TAoCP and its Influence of Computer Science : Richard Stallman : Linus Torvalds  : Larry Wall  : John K. Ousterhout : CTSS : Multix OS Unix History : Unix shell history : VI editor : History of pipes concept : Solaris : MS DOS :  Programming Languages History : PL/1 : Simula 67 : C : History of GCC development :  Scripting Languages : Perl history   : OS History : Mail : DNS : SSH : CPU Instruction Sets : SPARC systems 1987-2006 : Norton Commander : Norton Utilities : Norton Ghost : Frontpage history : Malware Defense History : GNU Screen : OSS early history

Classic books:

The Peter Principle : Parkinson Law : 1984 : The Mythical Man-Month :  How to Solve It by George Polya : The Art of Computer Programming : The Elements of Programming Style : The Unix Hater’s Handbook : The Jargon file : The True Believer : Programming Pearls : The Good Soldier Svejk : The Power Elite

Most popular humor pages:

Manifest of the Softpanorama IT Slacker Society : Ten Commandments of the IT Slackers Society : Computer Humor Collection : BSD Logo Story : The Cuckoo's Egg : IT Slang : C++ Humor : ARE YOU A BBS ADDICT? : The Perl Purity Test : Object oriented programmers of all nations : Financial Humor : Financial Humor Bulletin, 2008 : Financial Humor Bulletin, 2010 : The Most Comprehensive Collection of Editor-related Humor : Programming Language Humor : Goldman Sachs related humor : Greenspan humor : C Humor : Scripting Humor : Real Programmers Humor : Web Humor : GPL-related Humor : OFM Humor : Politically Incorrect Humor : IDS Humor : "Linux Sucks" Humor : Russian Musical Humor : Best Russian Programmer Humor : Microsoft plans to buy Catholic Church : Richard Stallman Related Humor : Admin Humor : Perl-related Humor : Linus Torvalds Related humor : PseudoScience Related Humor : Networking Humor : Shell Humor : Financial Humor Bulletin, 2011 : Financial Humor Bulletin, 2012 : Financial Humor Bulletin, 2013 : Java Humor : Software Engineering Humor : Sun Solaris Related Humor : Education Humor : IBM Humor : Assembler-related Humor : VIM Humor : Computer Viruses Humor : Bright tomorrow is rescheduled to a day after tomorrow : Classic Computer Humor

The Last but not Least Technology is dominated by two types of people: those who understand what they do not manage and those who manage what they do not understand ~Archibald Putt. Ph.D

The statements, views and opinions presented on this web page are those of the author (or referenced source) and are not endorsed by, nor do they necessarily reflect, the opinions of the Softpanorama society. We do not warrant the correctness of the information provided or its fitness for any purpose. The site uses AdSense so you need to be aware of Google privacy policy. You you do not want to be tracked by Google please disable Javascript for this site. This site is perfectly usable without Javascript.

Last modified: July 28, 2019;