Struggling with GREP commands, removing decimal point correctly

Question

I've written the shell command below to output the CPU's clock speed as an integer:

grep -m 1 'cpu MHz' /proc/cpuinfo | grep -o -E '[0-9]+'

OUTPUT:

900
063

This is because the exact clock speed is 900.063. Essentially, I want the command to return the 900 part but not the part after the decimal (.063).

Any help is much appreciated, thanks.

Answer 1

This might be easier done in awk:

awk -F: '/cpu MHz/ {print int($2); exit}' /proc/cpuinfo

• -F: - split on :
• /cpu MHz/ on lines matching cpu MHz, do:
  • {print int($2); exit}' - convert second field to integer, print it and exit (so we get only the first match)

Answer 2

There are many possibilities. Here's another one:

grep -m 1 'cpu MHz' /proc/cpuinfo | cut -f2 -d: | cut -f1 -d.

Answer 3

Below is Try

command

sed -n '/cpu MHz/s/.*://p' /proc/cpuinfo | sed "s/\..*//g"

Awk method

awk  -F ":" '/cpu MHz/{gsub(/\..*/,"",$NF);print $NF}' /proc/cpuinfo

python

#!/usr/bin/python
import re
k=re.compile(r'cpu MHz')
m=open('/proc/cpuinfo','r')
for i in m:
    if re.search(k,i):
        print i.split(":")[-1].split(".")[0]

Answer 4

Using sed is

grep -m 1 'cpu MHz' /proc/cpuinfo | sed -r 's/^(.*? )([0-9]+)(\..+)$/\2/g'

Answer 5

With grep:

grep -om1 'cpu MHz[^.]*' /proc/cpuinfo | grep -o '[[:digit:]]*'

Get the line without the dot and the following characters, then grep for the digits.

If your grep supports Perl-compatible regular expressions (PCRE):

grep -oPm1 'cpu MHz.* \K[[:digit:]]+' /proc/cpuinfo

Everything before the \K is matched as usual, but not included in the output (variable length lookbehind).

Answer 6

Adding some anchor (like the leading space) should give you what you need:

$ grep -m 1 '^cpu MHz' /proc/cpuinfo | grep -oE ' [0-9]+'
 900

If the leading space on the output is a problem, you can anchor on the dot:

$ grep -m 1 '^cpu MHz' /proc/cpuinfo | grep -oE '[0-9]+\.'
900.

If both space and dot are a problem, we need to step up to a higher level regex, PCRE:

$ grep -oPm 1  '^cpu MHz.* \K[0-9]+(?=\.)' /proc/cpuinfo
900

Which checks both the space and dot, but prints neither.

An equivalent with sed may be:

$ sed -nE 's/^cpu MHz.* ([0-9]+)\..*$/\1/p;T;q' /proc/cpuinfo
900

And with awk:

$ awk -F '[ .]' '/^cpu MHz/{print $3;exit}' /proc/cpuinfo
900

Answer 7

avg:

awk '/cpu MHz/{SUM+=$NF; LINE+=+1}END {printf "%0d" ,SUM/LINE}' /proc/cpuinfo