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Questions tagged [files]

Manipulating files: copying, renaming, searching, analyzing, archiving, etc. For operating on text in a file, see /text-processing. For questions about the Files file manager (formerly Nautilus), see /nautilus.

165
votes
6answers
17k views

Why is looping over find's output bad practice?

This question is inspired by Why is using a shell loop to process text considered bad practice ? I see these constructs for file in `find . -type f -name ...`; do smth with ${file}; done and for ...
31
votes
5answers
20k 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 ...
15
votes
3answers
5k 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 ...
19
votes
4answers
66k 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 ...
25
votes
4answers
19k 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 ...
150
votes
16answers
220k 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 ...
32
votes
3answers
4k 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 ...
88
votes
3answers
69k 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 ...
58
votes
6answers
134k 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% ...
122
votes
9answers
168k 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 ...
114
votes
10answers
222k views

Script to monitor folder for new files?

How to 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 ...
62
votes
5answers
96k views

How to determine which process is creating a file? [duplicate]

Given file path, how can I determine which process creates it (and/or reads/writes to it)?
29
votes
8answers
78k views

Test if there are files matching a pattern in order to execute a script

I am trying to write an if statement to test whether there are any files matching a certain pattern. If there is a text file in a directory it should run a given script. My code currently: if [ -f /*...
2
votes
5answers
2k 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 ...
120
votes
5answers
117k 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, ...
148
votes
6answers
79k 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: ...
18
votes
4answers
10k 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 any ...
15
votes
6answers
12k 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.
102
votes
7answers
290k 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.
108
votes
5answers
157k 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.
59
votes
4answers
51k 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. ...
42
votes
13answers
76k 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.
9
votes
8answers
6k views

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` ...
20
votes
4answers
23k 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 ...
6
votes
1answer
9k 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. I'...
110
votes
3answers
201k 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 ...
2
votes
5answers
3k 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 ...
208
votes
9answers
604k views

How to get over “device or resource busy”?

I tried to rm -rf a folder, and got "device or resource busy". In Windows, I would have used LockHunter to resolve this. What's the linux equivalent? (Please give as answer a simple "unlock this" ...
133
votes
4answers
383k views

Delete files older than X days +

I have found the command to delete files older than 5 days in a folder find /path/to/files* -mtime +5 -exec rm {} \; But how do I also do this for subdirectories in that folder?
101
votes
2answers
237k 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 ...
57
votes
4answers
22k 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 ...
24
votes
1answer
5k 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 ...
14
votes
7answers
18k 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?
10
votes
10answers
17k 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 ...
8
votes
4answers
2k views

How to print the name of missing files in a folder?

I have 2000+ files in a folder, but there are few files missing from the folder. Name of the files are like GLDAS_NOAH025SUBP_3H.A2003001.0000.001.2015210044609.pss.grb GLDAS_NOAH025SUBP_3H....
4
votes
2answers
3k 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 ...
131
votes
19answers
43k views

Is there an easy way to replace duplicate files with hardlinks?

I'm looking for an easy way (a command or series of commands, probably involving find) to find duplicate files in two directories, and replace the files in one directory with hardlinks of the files in ...
63
votes
3answers
78k views

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

How are character special files and block special files different from regular files in a Unix-like system? Why are they called “character special” and “block special” respectively?
121
votes
8answers
253k 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 . ...
89
votes
7answers
61k 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?
48
votes
3answers
159k 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 ...
34
votes
6answers
54k 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?
29
votes
4answers
5k views

Can a file that was originally sparse and then expanded be made sparse again?

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 ...
28
votes
1answer
1k 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 ...
22
votes
6answers
57k views

How to remove blank lines from a file in shell?

I want to remove all empty lines from a file. Even if the line contains spaces or tabs it should also be removed.
12
votes
3answers
3k views

A virtual file containing the concatenation of other files

Is there a way of creating a filesystem object akin to this: mknod files p cat file1 file2 ... fileN > files but such that it can be seeked in, as if it were a regular file?
4
votes
6answers
636 views

Concatenate multiple files with two blank lines as delimiter?

I'm trying to join Markdown files with two newlines between each file. I've tried using the following command: paste -sd '\n\n' file1.md file2.md This joins the files with a newline, but not two ...
3
votes
1answer
29k views

Shell script check if file exists?

I wrote a simple backup script which back ups my stuff on a remote server, everything is working great but I'd like to have some sort of report like "backup successful or not". this is my script # ...
225
votes
10answers
467k views

How to list all files ordered by size

I would like to list all files in the order of big to small in size and the files could be present anywhere in a certain folder.
76
votes
5answers
106k views

Understanding of diff output

I have file1.txt this is the original text line2 line3 line4 happy hacking ! and file2.txt this is the original text line2 line4 happy hacking ! GNU is not UNIX if I do: ...