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1500 questions
86
votes
4 answers

What does size of a directory mean in output of 'ls -l' command?

What does size of a directory mean in output of ls -l command?
Hemant
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86
votes
4 answers

Using OR patterns in shell wildcards

Contents of my dir are $ ls -lrt total 0 -rw-r--r-- 1 user1 admin 19 Oct 8 12:31 night.txt -rw-r--r-- 1 user1 admin 19 Oct 8 12:31 noon.txt -rw-r--r-- 1 user1 admin 38 Oct 8 12:31 day.txt I would like to list out details of files that have a…
mtk
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86
votes
3 answers

What happens when you delete a hard link?

If you do rm myFile where myFile is a hard link, what happens?
trusktr
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86
votes
6 answers

How can I safely remove a SATA disk from a running system?

I sometimes need to plug a disk into a disk bay. At other times, I have the very weird setup of connecting a SSD using a SATA-eSATA cable on my laptop while pulling power from a desktop. How can I safely remove the SATA disk from the system? This…
Lekensteyn
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86
votes
8 answers

Multiple arguments in shebang

I am wondering whether there is a general way of passing multiple options to an executable via the shebang line (#!). I use NixOS, and the first part of the shebang in any script I write is usually /usr/bin/env. The problem I encounter then is that…
Rastapopoulos
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86
votes
4 answers

How to run a script with systemd right before shutdown?

What do I need to put in the [install] section, so that systemd runs /home/me/so.pl right before shutdown and also before /proc/self/net/dev gets destroyed? [Unit] Description=Log Traffic [Service] ExecStart=/home/me/so.pl [Install] ?
sid_com
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86
votes
7 answers

Are threads implemented as processes on Linux?

I'm going through this book, Advanced Linux Programming by Mark Mitchell, Jeffrey Oldham, and Alex Samuel. It's from 2001, so a bit old. But I find it quite good anyhow. However, I got to a point when it diverges from what my Linux produces in the…
user147505
86
votes
7 answers

Bring down and delete bridge interface that's up

How do I remove a bridge that has an IP address that was brought up manually and isn't in /etc/network/interfaces? $ ifconfig br100 br100 Link encap:Ethernet HWaddr 00:00:00:00:00:00 …
Lorin Hochstein
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86
votes
3 answers

What is the 6th character of the password hash on Linux, and why is it often a slash?

On Linux, what is the sixth character of the password hash stored in /etc/shadow? On my puppy style linux box, if I try to generate 100 random passwords using shuf and /dev/urandom, then the sixth character is / about half the time. My question is…
insecure
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86
votes
8 answers

How to delete line with echo?

I know that I could delete the last three chars with: echo -ne '\b\b\b' But how can I delete a full line? I mean I don't want to use: echo -ne…
LanceBaynes
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86
votes
2 answers

Is there a whoami to find the current group I'm logged in as?

I'm trying to find my current logged in group without wanting to use newgrp to switch.
Ian F
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86
votes
5 answers

Run multiple commands and kill them as one in bash

I want to run multiple commands (processes) on a single shell. All of them have own continuous output and don't stop. Running them in the background breaks Ctrl-C. I would like to run them as a single process (subshell, maybe?) to be able to stop…
86
votes
3 answers

Joining bash arguments into single string with spaces

I'm trying to join all of the arguments to a Bash function into one single string with spaces separating each argument. I also need to have the string include single quotes around the whole string. Here is what I have so…
Schwagmister
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86
votes
5 answers

How to put a newline special character into a file using the echo command and redirection operator?

I would like to create a file by using the echo command and the redirection operator, the file should be made of a few lines. I tried to include a newline by "\n" inside the string: echo "first line\nsecond line\nthirdline\n" > foo but this way no…
Abdul Al Hazred
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86
votes
5 answers

why would curl and wget result in a 403 forbidden?

I try to download a file with wget and curl and it is rejected with a 403 error (forbidden). I can view the file using the web browser on the same machine. I try again with my browser's user agent, obtained by http://www.whatsmyuseragent.com. I do…
starfry
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