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RANDOMIZED THINGS FOR THE QUARK TOP

Admunix related things

Working as www-data "user"

sudo su - www-data -s /bin/bash

Network related things

DNS Server check with dig

Check this for details: https://jvns.ca/blog/2021/11/04/how-do-you-tell-if-a-problem-is-caused-by-dns

As a summary, try to get the website dns through:

$ dig iloveclim.eu

which, if functionnal will respond something like

iloveclim.eu.		3600	IN	A	78.196.23.159

Trying a non-existing sub-domain:

$ dig toto.iloveclim.eu
toto.iloveclim.eu.		IN	A

To check with a different name server, provide the nameserver ip as in (e.g. cloudfare):

$ dig @1.1.1.1 toto.iloveclim.eu

(this allows to check for DNS failures in current nameserver)

FORTRAN related things

Create a callgraph

We can use valgrind to create a callgraph as follows. After compiling the code with the -pg option run:

valgrind --dsymutil=yes --tool=callgrind myexec.x

After the run, obtained callgrind.out.1234 file can be processed with gprof2dot as:

gprof2dot.py -n0 -e0 ./callgrind.out.1992 -f callgrind > callgrind.out.1234.dot

Then use dot to create the actual graph:

dot -Tpng out.dot -o out.png

In the case you want to filter out the system calls from the graph, the solution of : https://stackoverflow.com/a/7774742 works like a charm.

start.txt · Last modified: 2025/09/30 12:42 by dokuroot