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8
votes
3answers
825 views

Why is cp --reflink=auto not the default behaviour?

Why is cp --reflink=auto not the default behaviour? Could it cause any harm to enable it? Is it possible to enable it at compile time, so it is used all across the system, not just in interactive ...
10
votes
2answers
374 views

/usr/bin/ptx: Can you provide a use case or two?

I was going through the list of files included in coreutils and I was able to come up with an example of how I could personally use all of the commands provided except for ptx. Can you give one or two ...
7
votes
3answers
3k views

How can I display octal notation of permissions with ls - and can octal represent all permissions? [duplicate]

After looking at the man page for ls on my system and searching Google, I see there IS a hack of way to use awk or perl to show octal permissions when using ls, but with bash is there anything more ...
5
votes
3answers
291 views

Which version of X introduced feature Y?

A big part of my daily job is developing software for use on machines with different versions of the same software, like bash, find, and grep. When encountering a feature which would be useful for ...
2
votes
3answers
254 views

When was a file last opened?

How do I determine, when a file was last opened? I've looked at man ls (using GNU coreutils 8.22) and I don't see anything about this timestamp.
8
votes
2answers
177 views

sort by hex value

Using coreutils sort, how can I sort numerically by a hexadecimal value (field)? I was expecting something along the lines of sort -k3,3x file_to_sort however, such an x does not exist. Edit: ...
2
votes
2answers
315 views

See extended attributes with coreutils ls on Mac

I have coreutils installed via MacPorts on my Mac running OS X 10.8.4. I have ls set to use the coreutils version of ls [(GNU coreutils) 8.21] when available: if [ -e /opt/local/libexec/gnubin ]; ...
0
votes
2answers
31 views

Where can I view a changelog for the sort command

I need to find sort's version when the -V flag was introduced. But I am finding myself some hard time finding the changelog for this command. Where can I view it?
7
votes
1answer
540 views

Is gnu coreutils sort broken?

Consider the following input to sort: cat > foo <<EOM D,,5014978 DD,,25 D,I,1972765530 D,Y,4223624 -,Y,71285059 YA,I,2 EOM Now try running sort foo The output is not sorted when trying ...
1
vote
2answers
37 views

numfmt invalid suffix input

I am using numfmt to convert a remote file's Content-Length from bytes to IEC format, i.e. 21M $ curl -sI http://jruby.org.s3.amazonaws.com/downloads/1.7.12/jruby-bin-1.7.12.tar.gz|grep Length|cut ...
1
vote
1answer
39 views

“install” command as script

I'm working on a heavily modified Linux based OS targeted for a really specific environment - easy-to-use NAS systems. It does not provide any GUI, apart from a web interface, but it at least has SSH. ...
27
votes
10answers
13k views

Correct locking in shell scripts?

Sometimes you have to make sure that only one instance of a shell script is running at the same time. For example a cron job which is executed via crond that does not provide locking on its own (e.g. ...
6
votes
3answers
3k views

Mac OS X: dircolors not found?

I just switched to a Macbook Air. I installed zsh using homebrew, but when I use some of the code that I (originally had) in my .zshrc, I get an error saying that .dircolors was not found. Below is ...
5
votes
2answers
253 views

How is the order in which tar works on files determined?

$ touch dir/{{1..8},{a..p}} $ tar cJvf file.tar.xz dir/ dir/ dir/o dir/k dir/b dir/3 dir/1 dir/i dir/7 dir/4 dir/e dir/a dir/g dir/2 dir/d dir/5 dir/8 dir/c dir/n dir/f dir/h dir/6 dir/l dir/m dir/j ...
2
votes
2answers
239 views

Has the GNU coreutils stat tool changed?

Has the GNU coreutils (8.6) version of stat changed? After a recent update, some scripts I wrote that call stat are not working as expected; in particular, I had been making use of stat -c %Y ...
27
votes
3answers
2k views

What is the `[` program that resides in my system's /bin?

I was recently browsing my Fedora's /bin folder and noticed a binary named [. I did try to search the internet for more information on that, but I couldn't find anything useful. Running it through ...
5
votes
3answers
6k views

Storing output of command in shell variable

I have an operation using cut that I would like to assign result to a variable var4=echo ztemp.xml |cut -f1 -d '.' I get the error: ztemp.xml is not a command The value of var4 never gets ...
4
votes
2answers
326 views

What does `du - hb` do?

With du -bh I think I get the apparent size in human readable format: # du -bh 295K ./test However, I would expect the same from du -hb, but I get something else: # du -hb 301926 ./test I ...
4
votes
2answers
931 views

Why is dd using direct slower writing to disk than to a file

I am trying to compare aggregate write rates when writing to a file in a GPFS file system, as compared to writing directly to a disk on a system with Red Hat Enterprise Linux Server release 6.4 ...
2
votes
3answers
2k views

cp --no-target-directory explained

Question: I need a simple example of how to use cp --no-target-directory. I do experience some difficulties in understanding cp --no-target-directory. I do understand the explanation for mv ...
1
vote
1answer
42 views

Memory-efficient utility to return N first sorted values

I would like to implement a very popular MapReduce example using only existing programs operating in a UNIX way. The problem is to find N most frequent values in an enormous amount of data. The ...
4
votes
2answers
68 views

Off by 1 year error in GNU date?

Right now, 2014-01-06, GNU date 8.4 on CentOS release 6.4, does this: $ date --date "last week" +"%Y-%V" 2013-01 On the other hand, $ date --date "last week" +"%Y-%U" 2013-52 which is just ...
0
votes
2answers
155 views

How can I format the output of stat to contain the null character?

I want to delimit file paths by using the null character (NUL, \0, ...) just like for example find -print0 does. I'm using bash and I tried the following without success: find $1 -print0 > ...
0
votes
1answer
125 views

what does the following command do?

what does the following command do? I have tried to study the linux command but I could not find out what this command does. here is the command: touch finger ; finger touch
3
votes
2answers
95 views

Ignore blank keys in coreutils sort

How do you ignore or is there a way to change the sort order of empty keys when using sort -k? # cat afile a b 11 20 93 45 55 26 09 31 How can I sort the empty column b values at the bottom so it ...
3
votes
2answers
247 views

cp -L vs. cp -H

Problem When copying files with cp -H or cp -L, I get the same results: $ ls -l fileA fileA -> fileB $ cp fileA somewhere/ -H $ ls -l somewhere/ fileA # fileA is a copy of fileB, only ...
2
votes
1answer
48 views

Checking the order of items in a shell environment variable

I am wanting to check that a certain directories always appear after other directories in an environment variable. List items are separated by a colon, as with the PATH variable. This is not simply ...
4
votes
3answers
2k views

convert soft- to hardlinks with cp

The cp command's infopage offers on the option --preserve= the following: links Preserve in the destination files any links between corresponding source files. Note that with -L' ...
3
votes
1answer
123 views

cp --attributes-only documented but not working “now”?

PROBLEM: cp --attributes-only Source Target results in two files unchanged, where the attributes from Source should be copied to Target. Attempts to solve: As I have the 8.13 version of coreutils ...
5
votes
3answers
174 views

What's the real point of the -f option on rm?

By reading the GNU coreutils man page for rm, one of the options is -f, which according to the manual, -f, --force ignore nonexistent files and arguments, never prompt Now, I made some ...
3
votes
1answer
3k views

Command to transpose (swap rows and columns of) a text file [duplicate]

Is there currently a generic command that will "pivot" input. e.g. #labeled.file name: bob title: code monkey name: joe title: pointy haired is converted to: name title bob code monkey joe ...
3
votes
2answers
224 views

tac command's option creates strange output [comprehension question]

Say I have this file, containing nothing but a b c b a Using tac --separator=a file in BASH [on a Debian based Linux], I get this: # empty line # empty line b c ...
4
votes
1answer
557 views

Install only a few GNU coreutils?

Is there a way to build and install only a few of the GNU coreutils? The README in coreutils-8.19.tar.xz lists 100-odd, but the INSTALL doesn't say how to install only a few, and the Makefile is (to ...
4
votes
1answer
95 views

Behavior of `du` command with `-L` flag

I've noticed a strange behavior with du command when it's used with -L command line option. I'm using Slackware 14 and Coreutils 8.19. To reproduce the strange behavior, create two folders: mkdir ...
1
vote
2answers
59 views

Checking compatibility between core utils and older GNU/Linux systems

I have non-root access to a grid of computers. The installed OS is the following: $ uname -mrs Linux 2.6.18-274.el5xen x86_64 $ cat /etc/*-release ...
1
vote
1answer
134 views

Is grep part of coreutils? (If not, why?)

I have read in a few websites that grep comes with coreutils (e.g. https://wiki.archlinux.org/index.php/Core_Utilities) However, after building them, I noticed that grep is missing. I wonder if I ...
3
votes
1answer
91 views

Print arguments to printf in no particular order

How can I refer back to arguments to coreutil's printf in no particular order? This is what I want to avoid: $ printf '%s %s %s %s %s %s %s' a c a c b c a a c a c b c a This is what I would like ...
1
vote
3answers
2k views

ls command - define number of columns

Is there a way to define the number of columns in ls output? I got this far: ls -C sorts in columns and ls -1 produces one column. --tabsize = option to produce two columns resulted in what looks ...
4
votes
1answer
85 views

How does coreutil's date manage to get such weird results?

I was playing around with date to try to convert expressions such as "2 hours" to a number of seconds like 7200. I thought I could perform this with invocations such as: date -d "1970-01-01 00:00:00 ...
7
votes
1answer
90 views

Is there a way to express: `--link` or fall back to ordinary copy in cp (from GNU coreutils)?

Is there a way to tell cp to --link (i.e. create hard links), but fall back in the case where I am attempting inter-device hardlinks? Inter-device links aren't possible and would cause cp to fail. ...
4
votes
4answers
484 views

Is there a practical use for the GNU factor command?

Looking through the GNU Coreutils, I spotted the factor command, that I had never noticed before. Reading the man page: Print the prime factors of each specified integer NUMBER. If none are ...
4
votes
4answers
2k views

Make cp return an error value if the target exists

Is there a way to make cp (from GNU coreutils on Linux) return a nonzero value in case the target file does already exist? Or is there any other small utility which is commonly available and which ...
9
votes
4answers
3k views

Any options to replace GNU coreutils on Linux?

I've been thinking about discontinuing the use of GNU Coreutils on my Linux systems, but to be honest, unlike many other GNU components, I can't think of any alternatives (on Linux). What alternatives ...
9
votes
2answers
569 views

What languages are used to build Unix commands?

Examples of commands I'm referring to are ls, pwd, and cd. Also, how are these built? Do you have an example?
2
votes
3answers
402 views

When the lines of a file or directory get too long, upgrade to ls list format?

Is there a way I can do this? For example if a gets a long name like: i-have-names-that-are-too-long-to-describe/ i-have-names-that-are-too-long-to-describe-2/ ...
12
votes
2answers
254 views

`test` and `[` - different binaries, any difference?

I noticed while answering another question that test and [ are different binaries, but the [ manpage pulls up test's. Besides the requirement for an ending ], is there any difference? If not, why are ...
8
votes
2answers
722 views

What is the point of ls -f (or, why is this hanging?)

I've got a directory with about 100,000 files in it. ls -f hangs for over a minute. I ran strace, and immediately started seeing getdents, so ls is clearly reading the directory. I also see a lot ...
4
votes
2answers
1k views

Trailing slashes on symbolic links to directories

I'm trying to emulate the process of path resolution (see man page path_resolution) in unix-like systems. My OS is Linux with GNU coreutils 8.7. In order to clarify the meaning of extra trailing '/' ...
2
votes
1answer
488 views

Why does unlink(1) support only one file?

I'm used to commands supporting multiple filename arguments if possible, but unlink doesn't: %> unlink a b unlink: extra operand `b' Try `unlink --help' for more information. I ended up using a ...
5
votes
2answers
3k views

GNU “install” -d flag — how's it work?

I'm trying to write a makefile rule to copy a directory, maintaining its structure, and since all the other rules in our makefiles use install, I wanted to be consistent. In the manpage, it says: ...