0
votes
0answers
32 views

Calculate Total disk i/o by a single process [duplicate]

I am looking for some tool that will dump total disk I/O by a single process after it ends. So far my finding is :- iotop= It shows i/o per process in real time but does not give total after process ...
2
votes
3answers
90 views

Is it possible to generate a separate file list when creating a tarball?

When using tar for backups I'd like to create a separate list of the files that is included in the archive for storing alongside the backup tarball. I also want to be able to store the error messages ...
23
votes
5answers
3k views

Why is iterating over a file twice faster than reading it into memory and computing twice?

I'm comparing the following tail -n 1000000 stdout.log | grep -c '"success": true' tail -n 1000000 stdout.log | grep -c '"success": false' with the following log=$(tail -n 1000000 stdout.log) echo ...
3
votes
1answer
304 views

Removing redirection operator does not change output. Why?

I saw this usage of redirection somewhere, and thought it was a typo: grep root < /etc/passwd But after I run it, I saw that it gives the same output with grep root /etc/passwd: $ grep root ...
6
votes
5answers
533 views

copy consumed output to stdout when stdout is redirected to a file

Given a command the output of which is being processed by, for example, grep I also want the actual output to be included in the log file for debugging purposes. For example if I have the following ...
12
votes
5answers
36k views

How can I read line by line from a variable in bash?

I have a variable which contains multiline output of a command. What's the most effecient way to read the output line by line from the variable? For example: jobs="$(jobs)" if [ "$jobs" ]; then ...