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1500 questions
253
votes
6 answers
How can I delete a word backward at the command line (bash and zsh)?
How can I delete a word backward at the command line? I'm truly used to some editors deleting the last 'word' using Ctrl+Backspace, and I'd like that functionality at the command line too.
I am using Bash at the moment and although I could jump…
lucidquiet
- 2,779
- 2
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253
votes
3 answers
Difference between 2>&-, 2>/dev/null, |&, &>/dev/null and >/dev/null 2>&1
Just looking for the difference between
2>&-
2>/dev/null
|&
&>/dev/null
>/dev/null 2>&1
and their portability with non-Bourne shells like tcsh, mksh, etc.
Det
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252
votes
4 answers
Why is FreeBSD deprecating GCC in favor of Clang/LLVM?
So I was surfing the net and stumbled upon this article. It basically states that FreeBSD, starting from Version 10 and above will deprecate GCC in favor of Clang/LLVM.
From what I have seen around the net so far, Clang/LLVM is a fairly ambitious…
NlightNFotis
- 7,525
- 7
- 32
- 38
252
votes
12 answers
How can I calculate the size of a directory?
How to know the size of a directory? Including subdirectories and files.
Juanjo Conti
- 2,683
- 2
- 15
- 7
251
votes
12 answers
How do I make my pc speaker beep
Using bash, how can I make the pc speaker beep?
Something like echo 'beepsound' > /dev/pcspkr would be nice.
Stefan
- 24,830
- 40
- 98
- 126
249
votes
6 answers
Can grep return true/false or are there alternative methods
As a part of this script, I need to be able to check if the first argument given matches the first word of file. If it does, exit with an error message; if it doesn't, append the arguments to the file. I understand how to write the if statement, but…
Lauren
- 2,555
- 2
- 15
- 9
249
votes
5 answers
What does env x='() { :;}; command' bash do and why is it insecure?
There is apparently a vulnerability (CVE-2014-6271) in bash: Bash specially crafted environment variables code injection attack
I am trying to figure out what is happening, but I'm not entirely sure I understand it. How can the echo be executed as…
jippie
- 13,756
- 10
- 44
- 64
248
votes
12 answers
linux: How can I view all UUIDs for all available disks on my system?
My /etc/fstab contains this:
# / was on /dev/sda1 during installation
UUID=77d8da74-a690-481a-86d5-9beab5a8e842 / ext4 errors=remount-ro 0 1
There are several other disks on this system, and not all disks are being mounted to…
Stefan Lasiewski
- 19,264
- 24
- 70
- 85
248
votes
20 answers
How can I get distribution name and version number in a simple shell script?
I'm working on a simple bash script that should be able to run on Ubuntu and CentOS distributions (support for Debian and Fedora/RHEL would be a plus) and I need to know the name and version of the distribution the script is running (in order to…
Alix Axel
- 2,879
- 4
- 17
- 13
248
votes
2 answers
Unzipping a .gz file without removing the gzipped file
I have a file file.gz, when I try to unzip this file by using gunzip file.gz, it unzipped the file but only contains extracted and removes the file.gz file.
How can I unzip by keeping both unzipped file and zipped file?
jack
- 3,853
- 11
- 28
- 33
246
votes
16 answers
Merging folders with mv?
If I use mv to move a folder called "folder" to a directory that already contains "folder" will they merge or will it be replaced?
Dominique
- 5,155
- 8
- 26
- 29
245
votes
14 answers
How to recursively find the amount stored in directory?
I know you are able to see the byte size of a file when you do a long listing with ll or ls -l. But I want to know how much storage is in a directory including the files within that directory and the subdirectories within there, etc. I don't want…
Rob Avery IV
- 3,075
- 3
- 17
- 14
245
votes
11 answers
Limit memory usage for a single Linux process
I'm running pdftoppm to convert a user-provided PDF into a 300DPI image. This works great, except if the user provides an PDF with a very large page size. pdftoppm will allocate enough memory to hold a 300DPI image of that size in memory, which…
Ben Dilts
- 2,553
- 3
- 13
- 5
245
votes
14 answers
Find the total size of certain files within a directory branch
Assume there's an image storage directory, say, ./photos/john_doe, within which there are multiple subdirectories, where many certain files reside (say, *.jpg). How can I calculate a summary size of those files below the john_doe branch?
I tried du…
mbaitoff
- 4,911
- 8
- 28
- 32
245
votes
5 answers
What is the 'working directory' when cron executes a job?
I have a script that works when I run it from the command line, but when I schedule it with cron I get errors that it cannot find files or commands. My question is twofold:
When I schedule a cron job using crontab -e, does it use my user ID as the…
ProfessionalAmateur
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