Ubuntu – Extract number from string

12.04command linescripts

When using this ubuntu command:

${HOME}/temp/.git describe --always --tags HEAD

the output of this command is:

v0.1.5-2-p343h3d3

I want to extract 1.5 from the output above and check if it's greater than 1.5 or not.
Is there any solution for this.?

Best Answer

You could do something like

${HOME}/temp/.git describe --always --tags HEAD  | awk ' {
                             match ($0, /[0-9]+\.[0-9]+\.[0-9]+/,m)
                             if(m[0]>"0.1.5"){ 
                                 print("hello")
                              }
                             }'

This will check the first matching regex result. Just throwing another way to do this, although I'm not sure how much of a practical way this is for you.

Cheers

Related Solutions

Ubuntu – How to remove lines from output containing a particular string

You can use grep -v to remove lines containing a string, such as '/proc', you could add this as a pipe to your command to make:

sudo find / -mmin -120 -printf '%T@ %p\n' | grep -v '^/proc' | sort -n | cut -f2- -d" " | more

However, as files in /proc/ are transitory in nature, you'll be likely to get some errors like

find: â?~/proc/22232/fdinfo/5â?T: No such file or directory

You can avoid these by redirecting the STDERR of the find command to /dev/null using, 2>/dev/null like so:

sudo find / -mmin -120 -printf '%T@ %p\n' 2>/dev/null | grep -v '^/proc' | sort -n | cut -f2- -d" " | more

A Better Method

Rather than filtering the results, and getting rid of your error messages, you can alter your find command so that it never looks in /proc:

sudo find / -not -path '/proc/*' -mmin -120 -printf '%T@ %p\n' | sort -n | cut -f2- -d" " | more

Ubuntu – How to extract only values greater than a threshold from a file

With `awk`

awk -F: '{if($2>10)print$2}' <filename

Explanations

-F: – sets the Field separator to :
{if($2>10)print$2} – for each line, test whether the 2nd field is >10, if so print it
<filename – let the shell open file filename, that's better than letting awk do that, see Stéphane Chazelas' answer on the topic

Example run

$ <filename awk -F: '{if($2>10)print$2}'
15.02
12.58

It's also possible to add spaces and put the pattern outside the brackets, so these are equal – thanks to Stefan for pointing that out:

awk -F: '{if($2>10)print$2}' <filename
awk -F: '{ if ( $2 > 10 ) print $2 }' <filename
awk -F: '$2>10{print$2}' <filename
awk -F: '$2 > 10 { print $2 }' <filename