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1500 questions
119
votes
8 answers

How to get the first word of a string?

When I echo * I get the following output: file1 file2 file3 ... What I want is to pick out the first word. How can I proceed?
vdegenne
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119
votes
13 answers

Replace environment variables in a file with their actual values?

Is there an easy way to substitute/evaluate environment variables in a file? Like let's say I have a file config.xml that contains: instanceId $INSTANCE_ID
119
votes
3 answers

What is "mail", and how is it navigated?

The program is located in /usr/bin/mail. Upon execution, Version 8.1.2 01/15/2001 is shown. Entering list produces: Commands are: next, alias, print, type, Type, Print, visual, top, touch, preserve, delete, dp, dt, undelete, unset, mail, mbox,…
cwd
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119
votes
13 answers

Is there any decent speech recognition software for Linux?

The short version of the question: I am looking for a speech recognition software that runs on Linux and has decent accuracy and usability. Any license and price is fine. It should not be restricted to voice commands, as I want to be able to dictate…
Franck Dernoncourt
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119
votes
1 answer

What happens when you 'mount over' an existing folder with contents?

Right now /tmp has some temporary files in it. When I mount my hard drive (/dev/sdc1) on top of /tmp, I can see the files on the hard drive. What happens to the actual content of /tmp when my hard drive is mounted? Is it possible to perform r/w…
user
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119
votes
4 answers

How to rsync a directory to a new directory with different name?

I'm doing a data transfer, the old file system relies deeply on a directory which now is on different path. This is a git directory which stores code online. I have no rights to move it or rename it. So what I can do is rsync this directory to the…
Zen
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119
votes
9 answers

How to view a specific process in top

Are there any relatively strightforward options with top to track a specific process? Ideally by identifying the process by a human readable value? e.g. chrome or java. In other words, I want to view all the typical information top provides, but for…
Michael Coleman
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119
votes
4 answers

Watch YouTube videos in terminal

I'm looking for a way to watch YouTube videos in terminal (not in a browser or another window, but right there, in any bash session). Is there a simple way to do this? I imagine something like this: $ youtube I already know how to…
Ionică Bizău
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119
votes
5 answers

Does tail read the whole file?

If I want to tail a 25 GB textfile, does the tail command read the whole file? Since a file might be scattered on a disk I imagine it has to, but I do not understand such internals well.
The Unfun Cat
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118
votes
6 answers

What is the difference between Halt and Shutdown commands?

What is the difference between the halt and shutdown commands?
wassimans
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118
votes
9 answers

Can't indent heredoc to match code block's indentation

If there's a "First World Problems" for scripting, this would be it. I have the following code in a script I'm updating: if [ $diffLines -eq 1 ]; then dateLastChanged=$(stat --format '%y' /.bbdata | awk '{print $1" "$2}' | sed…
Bratchley
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118
votes
3 answers

Why doesn't grep ignore binary files by default?

The manpage for grep describes the -I flag as follows: -I Ignore binary files. This option is equivalent to --binary-file=without-match option. It also says this about binary files: --binary-files=value Controls searching and…
user36078
118
votes
11 answers

Uploading directories with sftp?

I'm having some trouble uploading directories(which contain other directories a few levels deep) by sftp. I realize I could work around this by gzipping, but I don't see why that's necessary. Anyway, I try sftp> put bin/ Uploading bin/ to…
Earlz
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118
votes
5 answers

Command-line completion from command history

So, I've looked at history and at Ctrl+R, but they are not what I thought I knew. Is there a way that I can type in the beginning of a command, and cycle through the matches in my history with some bash shortcut? # mysq(some shortcut key) Gives…
Ben Dauphinee
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118
votes
7 answers

What are high memory and low memory on Linux?

I'm interested in the difference between Highmem and Lowmem: Why is there such a differentiation? What do we gain by doing so? What features does each have?
Navaneeth Sen
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