Life of a programmer
No hugs, kisses and dates
Anonymous
Only bugs, fixes and updates
No hugs, kisses and dates
Anonymous
Only bugs, fixes and updates
Recently, we were working on a Windows 10 machine on a metered connection. Even though we are not fans of blocking updates, this time we had to stop the updates as they were sucking the data package dry. To do so we executed the commands of the block below in a command prompt with administrative rights.
To start a Command Prompt (cmd
) with administrative rights we pressed Windows+X
that showed the Quick Access
menu, from the menu we clicked on Command Prompt (Admin)
. After that we got prompted by User Account Control
window if it was OK to allow this application to make changes, where we clicked Yes
.
In the new Command Prompt window we executed the following 3 commands that kill all services immediately related with the updates
1 2 3 | net stop wuauserv net stop bits net stop dosvc |
net stop wuauserv
stops the Windows Update service.net stop bits
stops the Background Intelligent Transfer Service servicenet stop dosvc
stops the Delivery Optimization serviceTo resume (actually restart them since we stopped them) the Windows 10 updates you can either restart the machine or in a command prompt with administrative rights execute the following:
1 2 3 | net start wuauserc net start bits net start dosvc |
Recently we were processing some results from an SQL query on the command line, we were grouping the results based on the first column of the query results and we wanted to add an empty line between each group of data.
Instead of messing with SQL specifics, we decided to use awk
to finish the task which resulted in the following code:
awk -F '|' -v column=1 'NR>1 && $column != previous { print "" } { previous = $column } { print $0 }'
-F fs
or --field-separator fs
: This option allowed us to choose the input field separator, in other words the character that should be used to split our text into columns. We used the value |
because that character is the default column delimiter for sqlite
.-v var=val
or --assign var=val
: We used the -v
option to define a variable to be used later on in the script. The value 1 was assigned to the variable column
before execution of the program began and it was available event to the BEGIN rule of the AWK
program. We did this to make the code a bit more modular, we could have just hardcoded the number in.NR>1 && $column != previous { print "" }
: Here we defined an if statement that checks two options: First we make sure that we are not on the first line of the input by using the NR>1
(and thus avoid creating an empty line which will be the first line of the output).previous
, it is on the next step). When both statements are true (we are not on the first row and the value of the column in the current row is different than the value of the column in the previous row) it will print out an empty line.{ previous = $column }
: This part is executed on ALL lines (even the first one) no matter what the values are. What this line does is to translate the value of the column
variable from being a number (the index of the column that we are interested in) into the actual value that the column has at that specific line. That value is then copied to the previous
variable to allow us to perform the check in the previous point once we move to the next line.{ print $0 }
: Finally, this part is also executed on all lines and it instructs awk
to print the input row whole and as is. This whole part could be replaced by a true value like the value 1
. In awk
as you see in this example, you define a series of operations. Each operation is constructed by a pattern to be matched and an action. Each pattern is evaluated for each input line, and in the cases where the pattern matches, the action is executed. The user can choose to omit either the pattern or the action for any operation. When a pattern is omitted, the action is executed on every line. When the action is omitted, then awk
will execute { print $0 }
. So, by adding a true value on its own it will be translated as on each line execute { print $0 }
which prints the whole row as is.1|1|0.0564904019731175 1|2|0.103176086258974 1|3|0.12910406904073 1|4|0.188592489201024 1|5|0.169676224898487 1|6|0.164690820027741 1|7|0.128458728519047 1|8|0.18549773544014 1|9|0.155677575617836 1|10|0.153941343314285 2|1|0.217221158956016 2|2|0.23390973064067 2|3|0.180231657220626 2|4|0.257673927303071 2|5|0.261393785194329 2|6|0.273441488895552 2|7|0.242815632929545 2|8|0.262269697286057 2|9|0.256054399760891 2|10|0.262613705138411 3|1|0.378589461360716 3|2|0.33008177312116 3|3|0.380973166776554 3|4|0.340431190160728 3|5|0.38189416214207 3|6|0.364842933594872 3|7|0.372958396398964 3|8|0.350010176652464 3|9|0.355815612501188 3|10|0.380553180349294
Will become
1|1|0.0564904019731175 1|2|0.103176086258974 1|3|0.12910406904073 1|4|0.188592489201024 1|5|0.169676224898487 1|6|0.164690820027741 1|7|0.128458728519047 1|8|0.18549773544014 1|9|0.155677575617836 1|10|0.153941343314285 2|1|0.217221158956016 2|2|0.23390973064067 2|3|0.180231657220626 2|4|0.257673927303071 2|5|0.261393785194329 2|6|0.273441488895552 2|7|0.242815632929545 2|8|0.262269697286057 2|9|0.256054399760891 2|10|0.262613705138411 3|1|0.378589461360716 3|2|0.33008177312116 3|3|0.380973166776554 3|4|0.340431190160728 3|5|0.38189416214207 3|6|0.364842933594872 3|7|0.372958396398964 3|8|0.350010176652464 3|9|0.355815612501188 3|10|0.380553180349294