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1500 questions
376
votes
13 answers
Prepending a timestamp to each line of output from a command
I wish to prepend a timestamp to each line of output from a command. For example:
foo
bar
baz
would become
[2011-12-13 12:20:38] foo
[2011-12-13 12:21:32] bar
[2011-12-13 12:22:20] baz
...where the time being prefixed is the time at which the line…
anon
375
votes
6 answers
Why does my shell script choke on whitespace or other special characters?
… or an introductory guide to robust filename handling and other string passing in shell scripts.
I wrote a shell script which works well most of the time. But it chokes on some inputs (e.g. on some file names).
I encountered a problem such as the…
Gilles 'SO- stop being evil'
- 829,060
369
votes
5 answers
How to set default file permissions for all folders/files in a directory?
I want to set a folder such that anything created within it (directories, files) inherit default permissions and group.
Lets call the group "media". And also, the folders/files created within the directory should have g+rw automatically.
Chris
- 8,540
- 5
- 23
- 18
368
votes
5 answers
How do I set an environment variable on the command line and have it appear in commands?
If I run
export TEST=foo
echo $TEST
It outputs foo.
If I run
TEST=foo echo $TEST
It does not. How can I get this functionality without using export or a script?
ashleysmithgpu
- 4,337
367
votes
4 answers
How do I clear Bash's cache of paths to executables?
When I execute a program without specifying the full path to the executable, and Bash must search the directories in $PATH to find the binary, it seems that Bash remembers the path in some sort of cache. For example, I installed a build of…
Daniel Trebbien
- 3,895
365
votes
10 answers
Change the Python3 default version in Ubuntu
I am using Ubuntu 16.04 LTS . I have python3 installed. There are two versions installed, python 3.4.3 and python 3.6 . Whenever I use python3 command, it takes python 3.4.3 by default. I want to use python 3.6 with python3.
python3 --version shows…
codeclue
- 3,763
364
votes
11 answers
How can I monitor disk io?
I'd like to do some general disk io monitoring on a debian linux server. What are the tools I should know about that monitor disk io so I can see if a disk's performance is maxed out or spikes at certain time throughout the day?
camomileCase
- 3,865
364
votes
18 answers
How do I set my DNS when resolv.conf is being overwritten?
Most of the info I see online says to edit /etc/resolv.conf, but any changes I make there just get overridden.
$ cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND…
Seán Hayes
- 4,541
363
votes
6 answers
How to define 'tab' delimiter with 'cut' in Bash?
Here is an example of using cut to break input into fields using a space delimiter, and obtaining the second field:
cut -f2 -d' '
How can the delimiter be defined as a tab, instead of a space?
Muhammad Hasan Khan
- 3,733
- 2
- 15
- 6
361
votes
3 answers
Hide curl output
I'm making a curl request where it displays an html output in the console like this
Warning: Cannot modify header information - headers already sent by (output started at…
Rjack
- 3,613
360
votes
4 answers
How to permanently set environmental variables
My variables are
LD_LIBRARY_PATH=/usr/lib/oracle/11.2/client64/lib
ORACLE_HOME=/usr/lib/oracle/11.2/client64
How to save these variables permanently ?
user3021349
- 16,569
355
votes
5 answers
How can I update to a newer version of Git using apt-get?
I've just set up a new machine with Ubuntu Oneiric 11.10 and then run
apt-get update
apt-get upgrade
apt-get install git
Now if I run git --version it tells me I have git version 1.7.5.4 but on my local machine I have the much newer git version…
cwd
- 45,389
354
votes
12 answers
How to know number of cores of a system in Linux?
I wanted to find out how many cores my system has, so I searched the same question in Google. I got some commands such as the lscpu command.
When I tried this command, it gave me the following result:
$ lscpu
Architecture: x86_64
CPU…
Mr ASquare
- 3,735
352
votes
22 answers
How can I run ssh-add automatically, without a password prompt?
I want to communicate between several computers on my network (static Ethernet), through SSH. In order to do that I need to run ssh-add every time I log in on a specific machine.
What can I do so it's set up once and it doesn't ask me for the…
zdun8
- 3,687
350
votes
4 answers
