Lorenzo Gaggini lgaggini

Using strace and lsof to debug blocked processes

You can use strace on a specific pid to figure out what a specific process is doing, e.g.:

strace -fp <pid>

You might see something like:

select(9, [3 5 8], [], [], {0, 999999}) = 0 (Timeout)

	rofi.kb-row-up: Up,Control+k,Shift+Tab,Shift+ISO_Left_Tab
	rofi.kb-row-down: Down,Control+j
	rofi.kb-accept-entry: Control+m,Return,KP_Enter
	rofi.terminal: mate-terminal
	rofi.kb-remove-to-eol: Control+Shift+e
	rofi.kb-mode-next: Shift+Right,Control+Tab,Control+l
	rofi.kb-mode-previous: Shift+Left,Control+Shift+Tab,Control+h
	rofi.kb-remove-char-back: BackSpace

	# Input: list of rows with format: "<filesize> filename", e.g.
	# filesizes.txt
	#######################
	# 1000K file1.txt
	# 200M file2.txt
	# 2G file3.txt
	#

	# Output:
	cat filesizes.txt \| numfmt --from=iec \| awk 'BEGIN {sum=0} {sum=sum+$1} END {printf "%.0f\n", sum}'

	#!/bin/bash

	#
	# This is sp, the command-line Spotify controller. It talks to a running
	# instance of the Spotify Linux client over dbus, providing an interface not
	# unlike mpc.
	#
	# Put differently, it allows you to control Spotify without leaving the comfort
	# of your command line, and without a custom client or Premium subscription.
	#

	# do it once
	seq 1 \| parallel -n0 "curl -H 'Content-Type: application/json' http://httpbin.org/post -X POST -d '{\"url\":\"http://google.com/\"}'"

	# do it twice
	seq 2 \| parallel -n0 "curl -H 'Content-Type: application/json' http://httpbin.org/post -X POST -d '{\"url\":\"http://google.com/\"}'"

	# do it 4 times, but at 2 a time
	seq 4 \| parallel -n0 -j2 "curl -H 'Content-Type: application/json' http://httpbin.org/post -X POST -d '{\"url\":\"http://google.com/\"}'"

	# you can also put all your commands into a file

	# Add the following line to your byobu keybindings.tmux file (~/.byobu/keybindings.tmux).
	# This will set the key combo ctrl-a, b (control plus 'a', then 'b') to copy the current byobu/tmux paste buffer to the X/Gnome clipboard.
	# This example uses parcellite to manage the X/Gnome clipboard so that, obviously, must be installed too.
	# parcellite might be able to be replaced with another tool like xsel but that hasn't been tested yet.

	bind b run-shell "tmux show-buffer \| parcellite > /dev/null >&1"

	#!/bin/bash

	# Author: Erik Kristensen
	# Email: [email protected]
	# License: MIT
	# Nagios Usage: check_nrpe!check_docker_container!_container_id_
	# Usage: ./check_docker_container.sh _container_id_
	#
	# Depending on your docker configuration, root might be required. If your nrpe user has rights
	# to talk to the docker daemon, then root is not required. This is why root privileges are not