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

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6
votes
5answers
4k views

How do you write specific bytes to a file?

Given a file myfile with the following contents: $ cat myfile foos A hexdump of the file gives us the contents: $ hexdump myfile 6f66 736f 000a Currently, I can create the file by specifying the ...
1
vote
3answers
48 views

Remove duplicate entries from a CSV file

I've got a [csv] file with duplicate datum reprinted ie the same data printed twice. I've tried using sort's uniq by sort myfile.csv | uniq -u however there is no change in the myfile.csv, also I've ...
2
votes
1answer
31 views

Copy files that partially matches another files in another location

I have a list of jpeg files in a directory like this (below is just a sample, like the structure is the same but this there are many fo0# sub-folders, not only fo01 and fo01, where each of these ...
2
votes
1answer
35 views

Remove newlines in file names

I have a PHP code that generates the file name on which wget will append its logs. I generated 2000+ files, but the problem is I am having trouble working with them because I had a mistake of putting ...
0
votes
1answer
405 views

Simple bash script taking too long to execute

I wrote the following function in my .bashrc for use instead of rm * : function re() { cp . -R /home/glset/ritwik/trash/ rm * } It works .. but it is very slow. Even for small files it takes ...
3
votes
2answers
146 views

Meaning of `cat /dev/null > file`

In a document created by a former coworker there is this command: cat /dev/null > /var/spool/mail/root It says next to it that it will clean out mailbox. Can someone please explain how/why ...
0
votes
0answers
34 views

File not read by Java until touched

We had a freak incident on Solaris. Our java program couldn't read a file until we touched the file. It was reading other files just fine, it just seemed to be completely blind to this one particular ...
2
votes
2answers
517 views

Matching two files for similar first line

I have 2 set of files. File one contains ID's ex: 1111 2222 6666 3333 4444 File two contains ID and username: 1873 Neil 1111 Roger 7632 Tim 3333 Oscar 8723 Greg 4444 Roy 6666 Patrick I want to ...
2
votes
4answers
422 views

Change to the last modified subdirectory of the current directory

I have an application which generates a couple of files in different directories at a regular interval and I need to check the latest files generated, i.e. the file which is generated in the most ...
2
votes
2answers
110 views

Script to determine if files are Images

I would like to create a shell script that will check to make sure all files in a directory are image files. We recently had an issue where a hacker was able to generate a file in a directory and ...
0
votes
2answers
32 views

How to pass arguments to perl when trying to change a line?

I am using the approach suggested in http://askubuntu.com/questions/434051/how-to-replace-a-string-on-the-5th-line-of-multiple-text-files to modify the first line of an archive. Let's suppose the ...
2
votes
2answers
61 views

File with permissions ---S--l---

Can some one explain what the meaning of these attributes: ---S--l---? When and why need to set this attribute? and for what? $ ls -ltr ---S--l--- 1 root root 0 Mar 10 ...
3
votes
1answer
84 views

I installed Ubuntu instead of Windows. Where are my files from D drive?

I'm quite new in Linux. I have had a Windows and two drives: C and D. Windows was on C. Then I installed Ubuntu instead of Windows, and I expected my files on D will stay. But I can't find it. As far ...
4
votes
1answer
58 views

Can I limit the size of the linux file cache?

I am running 64-bit Xubuntu 14.04, linux version 3.8.0-25 with 8GB of RAM. I have a script (in MATLAB, for what it's worth) that loads a large number of data files (~23k) one at a time, for a total ...
3
votes
2answers
49 views

Back up and restore file permissions

Is there a way to back up and restore file ownership and permissions (the things that can be changed with chown and chmod)? You can do this in Windows using icacls. What about access control lists?
16
votes
4answers
10k 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?
2
votes
1answer
34 views

Using inotifywait along with vim

I have simple script that monitors file for changes and rsyncs it with remote copy: #!/bin/bash while inotifywait -e close_write somefile do rsync somefile user@host.domain:./somefile done It ...
1
vote
4answers
107 views

Script to delete files that don't match certain filenames

I have a folder with 500,000 images, sorted in subfolders by year and month. I'd like to create a script that does this: If the filename does not match any of the filenames in names.log then delete ...
1
vote
1answer
3k views

Run .sh file instead of opening it

I am using Zorin OS 7. I want to run a .sh file but I can't seem to be able to—it just opens in a text editor. Also under RMB>open with there is no other option.
1
vote
1answer
48 views

Dynamic ~/.ssh/config

I'd like make my ~/.ssh/config file dynamically generated by a shell script (or anything else that prints to STDOUT). Is there a UNIX trick to make reading a file result in executing a command & ...
2
votes
0answers
36 views

Higher-level wrapper for entr or inotifywait

I'm looking for a way to rerun a specific command as soon as any of the files in a subdirectory (perhaps minus selected excludes) changes. Use case I'm working on a project that is self-contained in ...
1
vote
3answers
27 views

Should I put old projects in tarballs

I never really used tarballs/archived much, except for uploads (with compression). Now I've accumulated a huge list of software projects coding experiments -- basically directories with lots and lots ...
4
votes
6answers
689 views

How do I grep recursively through .gz files?

I am using a script to regularly download my gmail messages that compresses the raw .eml into .gz files. The script creates a folder for each day, and then compresses every message into its own file. ...
3
votes
3answers
105 views

Moving an open file to a different device

I have an application running that is generating a large (~200GB) output file, and takes about 35 hours to run (currently I'm about 12 hours in). The application just opens the file once then keeps it ...
6
votes
2answers
958 views

How to make a temporary file in RAM?

I have a script that will pipe its output to |tee scriptnameYYMMDD.txt. After each cycle of the for loop in which the output is generated, I'll be reversing the file contents with tac ...
1
vote
2answers
97 views

How to get file permission in octal

I have set of linux folders and I need to get the permissions of the folders numerically. For example in the below directory, I need to what is the permission value of the folder... Whether 755, 644 ...
1
vote
3answers
42 views

How to can I make Filename Sequencing with the help of Loops

my intention is to keep the code as simple as possible.Here there are 5 files namely A_1.CSV, A_2.CSV, A_3.CSV, A_4.CSV, A_5.CSV The below code retrieves the first row in a CSV file. Code : ...
0
votes
1answer
24 views

Which way is safer to read data from /sys

I am attempting to write a program that will monitor the temperature of various hardware components. The language I chose for it is Java. Now there are two ways I could read the temperatures: a) Do ...
2
votes
2answers
103 views

How to rename thousands of files efficiently?

I have a bunch of music files (literally thousands of files) in my Fedora PC that I'd like to rename with two rules: Every space must be replaced by the character _ (underscore), and Every letter in ...
1
vote
2answers
125 views

How do I move a line in a text file up or down by one line?

I have some text files, and I'd like to be able to move an arbitrary line in any of the files up or down one line (lines at the beginning or end of the file would stay where they are). I have some ...
4
votes
2answers
74 views

Use lines in a file to produce string and file name

I have a file, foo.txt, that has a folder name on each line: folder_1 folder_2 folder_3 And I'd like to do something like this: cat foo.txt | xargs -I {} echo 'function {}() { return stuff; }' ...
1
vote
1answer
32 views

Batch rename “case duplicates”

I have a folder on my Linux system that is cross-synchronized with other computers, some of them with Windows. The problem is that in that folder there are files that are "case duplicates", i.e. their ...
2
votes
0answers
98 views

Random file showing up in various directories. How to trace its creator?

I am finding a 0 byte file named ^- (that is a caret and a dash) in various directories on my file system. I use zsh with oh-my-zsh and I am pretty sure something in there is creating it but I really ...
1
vote
0answers
24 views

FS on NFS share responding slow

We have two server ex name app1 and app2.Both server have a nfs mount from same server as below:- nfsserver:/prlocal 249G 190G 46G 81% /prlocal Now the problem is when we try to access the FS ...
2
votes
2answers
26 views

Network drives in the cloud?

Is there such a service that allows Linux servers to access remote cloud storage as if it were a file on a local network? I'm running a very small server, 512 MB RAM and 20 GB hard drive space, but do ...
3
votes
1answer
55 views

Edit a file via a script yet maintain the osx tags

On OSX you can have tags which allows you to identify different categories of files. Here are two text files with different tags when viewed in Finder: I have a large number of these files and have ...
1
vote
1answer
74 views

pass all files in directory as one argument to perl script

linux beginner here I have a directory with 50 files in it and I want to simultaneously pass them all to a perl script with just a space between names , as in... ./perl_script.pl file1 file2 file3 ...
6
votes
3answers
896 views

Best way to swap filenames

I need to swap filenames of two files (file and file_1). I'm using the following code for it. mv file .phfile mv file_1 file mv .phfile file This works but is very buggy, It sometimes even results ...
1
vote
1answer
86 views

Swap two files in bash [duplicate]

How do I swap two files in Linux console with minimum typing? Boring approach: $ mv file1.dat fileX.dat $ mv file2.dat file1.dat $ mv fileX.dat file2.dat
0
votes
0answers
36 views

getting ? in permissions when running ll/ls command

I am trying to remove a folder and I am getting rm: cannot remove ‘...' when running the ll command I am getting : > ll ./folder/ ls: cannot access ./folder: Input/output error total 64 ...
4
votes
2answers
509 views

How to copy files *to* a camera?

I'd like to copy a firmware update file to my Canon 7D camera, connected via USB. After it was auto-mounted by thunar + thunar-volman + gvfs-gphoto2 I tried the following: $ cp ...
4
votes
2answers
105 views

How to delete part of a binary file without copying

I need to delete the first 2 bytes of a 6MB file. However, this is an embedded Linux with only 32 Mbytes RAM and less than 1 MB free flash memory. I tried using dd, as: 1 - # dd bs=1 skip=2 ...
16
votes
4answers
25k views

File extensions for unix shell scripts

On wikipedia, the article for .sh says: For the .sh file extension type, see Bourne shell. How about other unix shells? I know that the shebang is used inside the file to indicate an ...
0
votes
1answer
24 views

Relationship between file properties and user and group

There is something not clear on relationship between file properties and user and group. root@debian:/home/debian# ls -l /home/linuxsir total 4 -rw-r--r-- 1 linuxsir root 1549 Feb 23 19:16 ...
-3
votes
1answer
49 views

find all .sh files then copy to <date>scriptbackup

Locate all the .sh scripts you have created in your Linux installation (searching recursively if needed – excluding existing backup folders) It will then copy them all into a folder called ...
4
votes
4answers
3k views

Redirecting Output of print to multiples files in awk

I want to print same lines to 2 different files. What I am doing right now is: print ID[i]" "Value[i]" "TS1[i]" "TS2[i] > "file1.txt"; print ID[i]" "Value[i]" "TS1[i]" "TS2[i] > "file2.txt"; ...
0
votes
1answer
24 views

Print output of some my data in a file that should start with first line without blank space

By using some shell command i filter some output Please can some one suggest how i can print this output in some file For example I filtered some line and save it to some file but problem is it is ...
31
votes
7answers
2k views

How can I trick a process into thinking a file doesn't exist?

I have a program that stores its settings in ~/.config/myprogram that I use both interactively and with a batch queuing system. When running interactively, I want this program to use my configuration ...
1
vote
1answer
18 views

Rename command with non-existing target directory

I'm trying to group files automatically into subdirectories using a command like this: $ rename 's/(.)(.)(.+)/$1\/$2\/$1$2$3/' *.* A dry run with the -n parameter shows me what I want: test.jpg ...
0
votes
2answers
29 views

How to specify the file type in a hard link [closed]

Does anyone know how to specify the file type of a hard link? Is this even possible? For example, I want to link to an HTML file (with content type text/html) in my website directory, so I used ln ...