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1500 questions
3 answers

Why does man print "gimme gimme gimme" at 00:30?

We've noticed that some of our automatic tests fail when they run at 00:30 but work fine the rest of the day. They fail with the message gimme gimme gimme in stderr, which wasn't expected. Why are we getting this output?
Jaroslav Kucera
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16 answers

How do I get the size of a directory on the command line?

I tried to obtain the size of a directory (containing directories and sub directories) by using the ls command with option l. It seems to work for files (ls -l file name), but if I try to get the size of a directory (for instance, ls -l /home), I…
Abdul Al Hazred
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10 answers

What is the exact difference between a 'terminal', a 'shell', a 'tty' and a 'console'?

I think these terms almost refer to the same thing, when used loosely: terminal shell tty console What exactly does each of these terms refer to?
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12 answers

How to correctly add a path to PATH?

I'm wondering where a new path has to be added to the PATH environment variable. I know this can be accomplished by editing .bashrc (for example), but it's not clear how to do this. This way: export PATH=~/opt/bin:$PATH or this? export…
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12 answers

How to copy files from one machine to another using ssh

I am using a Linux (CentOS) machine, and I have already connected to another system using SSH. Now, my question is: How can I copy files from one system to another system? Suppose, in my environment, I have two system like System A and System B. I'm…
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9 answers

How to install a deb file, by dpkg -i or by apt?

I have a deb package for installation. Shall I install by dpkg -i my.deb, or by apt? Will both handle the software dependency problem well? If by apt, how can I install from the deb by apt?
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10 answers

How can I replace a string in a file(s)?

Replacing strings in files based on certain search criteria is a very common task. How can I replace string foo with bar in all files in the current directory? do the same recursively for sub directories? replace only if the file name matches…
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6 answers

How to see full log from systemctl status service?

I check service status with systemctl status service-name. By default, I see few rows only, so I add -n50 to see more. Sometimes, I want to see full log, from start. It could have 1000s of rows. Now, I check it with -n10000 but that doesn't look…
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3 answers

How to unfreeze after accidentally pressing Ctrl-S in a terminal?

It's a situation that has happened quite often to me: after I press (with a different intention) Ctrl-S in a terminal, the interaction (input or output) with it is frozen. It's probably a kind of "scroll lock" or whatever. How do I unfreeze the…
imz -- Ivan Zakharyaschev
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2 answers

Why was '~' chosen to represent the home directory?

I have often wondered why the ~ (tilde) character represents the home directory of a user. Is there a reason behind this, or is it just because tilde is an infrequently used character?
Lelouch Lamperouge
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2 answers

How do I make `ls` show file sizes in megabytes?

What commands do I need for Linux's ls to show the file size in MB?
Paul Sheldrake
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12 answers

How can I reduce a video's size with ffmpeg?

How can I use ffmpeg to reduce the size of a video by lowering the quality (as minimally as possible, naturally, because I need it to run on a mobile device that doesn't have much available space)? I forgot to mention that when the video can use…
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13 answers

How do I grep for multiple patterns with pattern having a pipe character?

I want to find all lines in several files that match one of two patterns. I tried to find the patterns I'm looking for by typing grep (foo|bar) *.txt but the shell interprets the | as a pipe and complains when bar isn't an executable. How can I…
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4 answers

How to cycle through reverse-i-search in BASH?

In the terminal, I can type Ctrl + R to search for a matching command previously typed in BASH. E.g., if I type Ctrl + R then grep, it lists my last grep command, and I can hit enter to use it. This only gives one suggestion though. Is there any way…
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5 answers

What does "--" (double-dash) mean?

I have seen -- used in the compgen command. For example: compgen -W "foo bar baz" -- b What is the meaning of the -- in there?
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