GNU Core Utilities are the GNU project's implementation of the core command-line tools of a POSIX system, including tools like ls, cp, mv, rm, etc.

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Storing output of command in shell variable [duplicate]

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 ...
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votes
11answers
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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. ...
12
votes
2answers
282 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
1answer
660 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 ...
11
votes
3answers
693 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 ...
4
votes
2answers
380 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 ...
2
votes
3answers
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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 ...
8
votes
2answers
880 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 ...
5
votes
2answers
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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 '/' ...
12
votes
4answers
2k 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 ...
4
votes
3answers
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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' ...