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Appending a line to a file only if it does not already exist
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Just keep it simple :)
grep + echo should suffice:
grep -qxF 'include "/configs/projectname.conf"' foo.bar || echo 'include "/configs/projectname.conf"' >> foo.bar
-q be quiet
-x match the whole line
-F pattern is a plain string
https://linux.die.net/man/1/grep
Edit:
inco...
How to write a cron that will run a script every day at midnight?
...--0 minutes and 0 hours--and the *s mean every day of every month.)
Syntax:
mm hh dd mt wd command
mm minute 0-59
hh hour 0-23
dd day of month 1-31
mt month 1-12
wd day of week 0-7 (Sunday = 0 or 7)
command: what you want to run
all numeric values can be replaced by * which mean...
In PHP, can you instantiate an object and call a method on the same line?
... @CMCDragonkai logically that makes sense; the object only exists for the duration of the statement (new Foo)->property - the value you are storing has nowhere to go because the object will no longer exist after that as it's not stored anywhere.
– thomasrutter...
How to do a non-greedy match in grep?
...ng for a non-greedy (or lazy) match. To get a non-greedy match in regular expressions you need to use the modifier ? after the quantifier. For example you can change .* to .*?.
By default grep doesn't support non-greedy modifiers, but you can use grep -P to use the Perl syntax.
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Using vagrant to run virtual machines with desktop environment
... development environment is based on virtual machines, running on VirtualBox. We would like to move one step further, and use the capabilities of Vagrant to have the description of the machine in a text file and then be able to "raise" that machine based on that text file. Combined to puppet, this w...
What is the MIME type for Markdown?
Does anyone know if there exists a MIME type for Markdown? I guess it is text/plain , but is there a more specific one?
4 ...
How do I determine the size of my array in C?
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Executive summary:
int a[17];
size_t n = sizeof(a)/sizeof(a[0]);
Full answer:
To determine the size of your array in bytes, you can use the sizeof
operator:
int a[17];
size_t n = sizeof(a);
On my computer, ints are 4 ...
Fastest method to replace all instances of a character in a string [duplicate]
...g/character in a string in JavaScript? A while , a for -loop, a regular expression?
14 Answers
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Line-breaking widget layout for Android
...aining the words. As space required for all 'words' in a 'sentence' would exceed the available horizontal space on the display, I would like to wrap these 'sentences' as you would a normal piece of text.
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How to debug Lock wait timeout exceeded on MySQL?
... see the affected table(s)
You get all kinds of additional Locking and Mutex Information.
Here is a sample from one of my clients:
mysql> show engine innodb status\G
*************************** 1. row ***************************
Type: InnoDB
Name:
Status:
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