Use this tag for questions about file management and operations on files.

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238
votes
6answers
460k views

How can I replace a string in a file(s)?

Replacing strings in files based on certain search criteria is a very common task. How can I replace string foo with bar in all files in the current directory? do the same recursively for sub ...
13
votes
4answers
5k views

Is it possible to find out what program or script created a given file?

Three files have suddenly appeared in my home directory, called "client_state.xml", "lockfile", and "time_stats_log". The last two are empty. I'm wondering how they got there. It's not the first time ...
32
votes
3answers
3k views

Can a bash script be hooked to a file?

I want a script to sleep unless a certain file is modifed/deleted (or a file created in a certain directory, or ...). Can this be achieved in some elegant way? The simplest thing that comes to my mind ...
7
votes
3answers
2k views

Create a virtual file that is actually a command

Is there any way to create a virtual file, such that reading from the file actually reads from the stdout of a command; writing to the file is acually writing to the stdin of a command? So far I have ...
12
votes
4answers
5k views

How to run a command when a directory's contents are updated?

There is a directory A whose contents are changed frequently by other people. I have made a personal directory B where I keep all the files that have ever been in A. Currently I just occasionally ...
39
votes
5answers
37k views

How to determine which process is creating a file?

Given file path, how can I determine which process creates it (and/or reads/writes to it)?
72
votes
5answers
24k views

What's the point in adding a new line to the end of a file?

Some compilers (especially C or C++ ones) give you warnings about: No new line at end of file I thought this would be a C-programmers-only problem, but github displays a message in the commit view: ...
56
votes
3answers
34k views

Why can rm remove read-only files?

If I create a file and then change its permissions to 444 (read-only), how come rm can remove it? If I do this: echo test > test.txt chmod 444 test.txt rm test.txt ...rm will ask if I want to ...
65
votes
6answers
54k views

How to remove duplicate lines inside a text file?

A huge (up to 2 GiB) text file of mine contains about 100 exact duplicates of every line in it (useless in my case, as the file is a CSV-like data table). What I need is to remove all the repetitions ...
54
votes
7answers
111k views

How to find creation date of file?

I want to find out the creation date of particular file, not modification date or access date. I have tried with ls -ltrh and stat filename.
31
votes
5answers
50k views

How can I increase the number of inodes in an ext4 filesystem?

I had a problem (new to me) last week. I have a ext4 (Fedora 15) filesystem. The application that runs on the server suddenly stopped. I couldn't find the problem at first look. df showed 50% ...
5
votes
3answers
1k views

Precedence of user and group owner in file permissions

I just ran into something unexpected (for me) regarding file permissions on Linux (Arch Linux). Basically I have: userX in groupX fileX userX:groupX ---rwx---- What puzzles me: I cannot perform ...
4
votes
1answer
5k views

Rename All Files with a Certain Name

I'm trying to find certain files with the name "stringx" and replace the name (but not the extension) with "stringy". So basically for stringx.txt and stingx.cs, I'd want stringy.txt and stringy.cs. ...
66
votes
6answers
57k views

What is a Superblock, Inode, Dentry and a File?

From the article Anatomy of the Linux file system by M. Tim Jones, I read that Linux views all the file systems from the perspective of a common set of objects and these objects are superblock, inode, ...
49
votes
3answers
65k views

How do I do a ls and then sort the results by date created?

In what order are the dated ordered by? Certainly not alphanumeric order. ls -lt sorts by modification time. But I need creation time.
27
votes
3answers
16k views

List the files accessed by a program

time is a brilliant command if you want to figure out how much CPU time a given command takes. I am looking for something similar that can list the files being accessed by a program and its children. ...
10
votes
3answers
10k views

How can I rename a lot of files using a regex?

I want to rename a lot of files on Mac OS X (10.7.2).. I don't have the perl package for the rename command. My files have names like "T452-102456-0.png" and I want to delete the "-0" part. I know I ...
4
votes
2answers
1k views

undelete files from local fileserver

I have a NAS (mybook world white light) in my living room where all my music and stuff is stored. I've mounted the music folder of the nas in the local music folder of my home directory on my desktop ...
40
votes
5answers
72k views

Script to monitor folder for new files?

How do I detect new files in a folder with a bash script? I would like to process the files as soon as they are created in the folder. Is this possible to do so or do I have to schedule a script with ...
24
votes
10answers
30k views

How to move 100 files from a folder containing thousands?

I have a directory with thousands of files. How can I move 100 of the files (any files will do) to another location.
24
votes
1answer
440 views

When did directories stop being readable as files?

I have the 1st edition of The Unix Programming Environment book. In chapter 2, the authors state that directories are readable as files, and mention some facts about the format of these files. They ...
7
votes
8answers
4k views

Bash, remove oldest files

I`m trying to delete old files from directory and leave only 3 newest files. cd /home/user1/test while [ `ls -lAR | grep ^- | wc -l` < 3 ] ; do rm `ls -t1 /home/user/test | tail -1` ...
1
vote
4answers
504 views

How does one inspect the directory structure information of a unix/linux file?

In Unix file systems directories are just special files with special directory structures that hold the child filename, filename size and inode reference number. The actual file metadata beyond ...
42
votes
2answers
88k views

timestamp, modification time, and created time of a file

I just know that ls -t and ls -f give different sorting of files and subdirectories under a directory. What are the differences between timestamp, modification time, and created time of a file? How ...
54
votes
5answers
31k views

Find duplicate files

Is it possible to find duplicate files on my disk which are bit to bit identical but have different file-names?
38
votes
8answers
86k views

List only regular files (but not directories) in current directory

I can use ls -ld */ to list all the directory entries in the current directory. Is there a similarly easy way to just list all the regular files in the current directory? I know I can use find find . ...
26
votes
5answers
22k views

How to list files that were changed in a certain range of time?

How can I list recursively all files that were changed between 22.12.2011 and 24.12.2011?
15
votes
4answers
2k views

Can a file that was originally sparse and expanded be made re-sparse

I know that copying or transferring what was originally a sparse file without using a utility that understands sparse files will cause the 'holes' to be filled out. Is there a method or utility to ...
10
votes
6answers
13k views

Shell script for moving oldest files?

How do I write a script for moving just the 20 oldest files from one folder to another? Is there a way to grab the oldest files in a folder?
8
votes
7answers
12k views

What's the best way to count the number of files in a directory?

If parsing the output of ls is dangerous because it can break on some funky characters (spaces, \n, ... ), what's the best way to know the number of files in a directory? I usualy rely on find to ...
7
votes
4answers
233 views

List all directories that do NOT have a file with a given file name inside

How would I go into listing all directories that do not have a file with a given file name inside? e.g. given this tree / /a README file001 file002 /b README file001 /c ...
42
votes
3answers
71k views

Find and remove large files that are open but have been deleted

How does one find large files that have been deleted but are still open in an application? How can one remove such a file, even though a process has it open? The situation is that we are running a ...
100
votes
3answers
96k views

How to tell gzip to keep original file?

I would like to compress a text file using gzip command line tool while keeping the original file. By default running the following command gzip file.txt results in modifying this file and renaming ...
21
votes
2answers
7k views

recursive statistics on file types in directory?

I did a website scrape for a conversion project. I'd like to do some statistics on the types of files in there -- for instance, 400 .html files, 100 .gif, etc. What's an easy way to do this? It has to ...
20
votes
4answers
3k views

Is there an “open with” command for the command line?

Does the command line have a way to get a recommended list of programs used to open a particular file, based on the file type? For example, a .pdf file would have an open with... recommendation using ...
17
votes
3answers
4k views

I accidentally chmod -R +x on a directory. How do I restore the correct permissions?

Well, to be specific, it was chmod -R 755. Now every file is executable, which I don't want. I am thinking that I should look at the first two bytes of each file for the #!, but will this cover ...
5
votes
4answers
26k views

Linux file access monitoring

Is there any way in unix to find out who accessed certain file in last 1 week? It may be user or some script ftp it to some other place. Can I get a list of user name who accessed certain file? How ...
15
votes
5answers
5k views

How can I edit a large file in place?

I have a few files sized > 1 GB each. I need to remove last few bytes from the files. How can I do it? I prefer to edit file in place to save disk space. I am on HP-UX.
10
votes
5answers
5k views

How to create a file even root user can't delete it

How to create a file even root user can't delete it ?
0
votes
5answers
137 views

Find all [filename].mp4 and rename [filename].audio [duplicate]

So I have a script that adds 2 films together using the audio from the $1.audio file. What I would like to do is rename any file in the directory with: *.mp4 To: *.audio Keeping original file ...
61
votes
12answers
78k views

Efficiently delete large directory containing thousands of files

We have an issue with a folder becoming unwieldy with hundreds of thousands of tiny files. There are so many files that performing rm -rf returns an error and instead what we need to do is something ...
22
votes
2answers
30k views

What are character special and block special files in a unix system?

How are character special files and block special files different from regular files in a Inix-like system? Why are they called “character special” and “block special” respectively?
60
votes
3answers
208k views

Get file created/creation time? [duplicate]

Possible Duplicate: How do I do a ls and then sort the results by date created? Is there a command in Linux which displays when the file was created ? I see that ls -l gives the last ...
20
votes
3answers
50k views

how to output text to both screen and file inside a shell script?

Currently I have a shell script which logs messages to a log file like this: log_file="/some/dir/log_file.log" echo "some text" >> $log_file do_some_command echo "more text" >> $log_file ...
20
votes
1answer
2k views

How to implement a horizontal cat? [duplicate]

Standard cat concatenates files line by line (row by row, if you will). I find myself needing a horizontal cat command more and more often recently; i.e. a command that takes a list of files and ...
13
votes
5answers
42k views

How do I append text to the beginning and end of multiple text files in Bash?

I have a directory full of text files. My goal is to append text to the beginning and end of all of them. The text that goes at the beginning and end is the same for each file. Based on code I got ...
10
votes
4answers
4k views

Can I make `cut` change a file in place?

The man page doesn't give me much hope, but I'm hoping it's an undocumented (and/or GNU-specific) feature.
21
votes
1answer
3k views

Who creates /etc/{group,gshadow,passwd,shadow}-?

In any linux system I have access to (a couple of Archlinuxes, an Ubuntu, a Debian Sid and a Gentoo) there are the following 4 files in /etc/, all ending with a dash: /etc/group- /etc/gshadow- ...
9
votes
4answers
13k views

Number of files containing a given string

How can I count the number of files (in a directory) containing a given string as input in bash/sh?
7
votes
1answer
13k views

Cannot delete a file - permission denied - why?

[db2inst1][testing ~/sqllib/db2dump] rm db2diag.log rm: cannot remove `db2diag.log': Permission denied [db2inst1][testing ~/sqllib/db2dump] id uid=1002(db2inst1) gid=107(db2iadm1) ...