how to read file line by line and delete the line have number less than 20% shell scripting

Question

i need help. i have this file i want read it line by line with for loops and delete the line less than 20% the number will with list %CPU .

%CPU   PID USER       UID COMMAND         %MEM
71  9136 ashti     1000 firefox          4.6
36  1432 ashti     1000 gnome-shell      8.6
25 9100 ashti     1000 gedit            1.1
 3  9092 ashti     1000 nautilus         1.2
 2  9109 ashti     1000 gnome-terminal-  0.9
 1 1248 ashti     1000 Xorg             2.6
 0  1375 ashti     1000 VBoxClient       0.0
 0  9118 ashti     1000 bash             0.1
 0   269 root         0 systemd-journal  2.8

i want be like this example

%CPU   PID USER       UID COMMAND         %MEM
71  9136 ashti     1000 firefox          4.6
36  1432 ashti     1000 gnome-shell      8.6
25 9100 ashti     1000 gedit            1.1

and save in new file .

best regards

please check this link its my code question [link] (https://unix.stackexchange.com/questions/549368/i-need-help-i-have-this-code-i-want-add-if-the-number-of-c-grater-than-2-pri) — kawa, Oct 29 '19 at 20:01
If you are using Ubuntu you can post these questions in [**Ask Ubuntu**](https://askubuntu.com/) What command did you use to generate the CPU%? It appears like it needs to be divided by the number of CPU cores for an accurate percentage. — WinEunuuchs2Unix, Oct 30 '19 at 00:09

score 2 · Answer 1 · answered Oct 29 '19 at 17:40

2

With grep:

grep -e "^%" -e "^[2-9][1-9]" file | column -t

column -t to make it pretty:

%CPU  PID   USER   UID   COMMAND      %MEM
71    9136  ashti  1000  firefox      4.6
36    1432  ashti  1000  gnome-shell  8.6
25    9100  ashti  1000  gedit        1.1

answered Oct 29 '19 at 17:40

schrodingerscatcuriosity

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score 1 · Answer 2 · answered Oct 29 '19 at 17:43

1

With retaining header, awk expression:

$ awk 'NR==1 || (NR > 1 && $1 > 20)' file
%CPU   PID USER       UID COMMAND         %MEM
71  9136 ashti     1000 firefox          4.6
36  1432 ashti     1000 gnome-shell      8.6
25 9100 ashti     1000 gedit            1.1

answered Oct 29 '19 at 17:43

RomanPerekhrest

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please check this link its my code question [link] (https://unix.stackexchange.com/questions/549368/i-need-help-i-have-this-code-i-want-add-if-the-number-of-c-grater-than-2-pri) – kawa Oct 29 '19 at 20:01

score 0 · Answer 3 · answered Oct 29 '19 at 18:00

0

A for loop is not a good choice for this task - for a discussion of the reasons why, see for example

Why is using a shell loop to process text considered bad practice?

My personal choice would be Miller:

$ mlr --pprint filter -x '${%CPU} < 20' file > newfile

$ cat newfile
%CPU PID  USER  UID  COMMAND     %MEM
71   9136 ashti 1000 firefox     4.6
36   1432 ashti 1000 gnome-shell 8.6
25   9100 ashti 1000 gedit       1.1

answered Oct 29 '19 at 18:00

steeldriver

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please check this link its my code question [link] (https://unix.stackexchange.com/questions/549368/i-need-help-i-have-this-code-i-want-add-if-the-number-of-c-grater-than-2-pri) – kawa Oct 29 '19 at 20:01

how to read file line by line and delete the line have number less than 20% shell scripting

3 Answers3