https://www.tutonics.com/2012/11/gpg-encryption-guide-part-1.html?m=1

#gpg #assymetric #cryptography

If you have multiple statements and you want to time the whole statements in a bash script you can use time command, but you don't need to use inside of the script. If you have an script called my_long_tasks.sh you need to just:

$ time my_long_tasks.sh
 real    0m20.894s
 user    0m3.664s
 sys     0m0.452s

That's it. In case you want to just time part of your statements in your bash script then you need to:

start=`date +%s`
 stuff
 end=`date +%s`

 runtime=$((end-start))

#linux #bash #time

In bash script you can get count of given arguments to your script using $#. If you want to get a positional argument use $ and then number like $1. If you want to get the exit code of the previous command use $?.

#linux #bash #script

#gpg #mail #encryption

https://gpgtools.tenderapp.com/kb/how-to/first-steps-where-do-i-start-where-do-i-begin-setup-gpgtools-create-a-new-key-your-first-encrypted-mail

#gpg #email #encryption #privacy

https://www.linode.com/docs/networking/nfs/how-to-mount-nfs-shares-on-debian-9/

#nfs #debian #mount #export #fstab

Table compression in MySQL:

https://dev.mysql.com/doc/refman/5.5/en/innodb-compression-usage.html

#database #mysql #compression #innodb

Sometimes you have to send a very large file over network to a remote destination, or want to copy a huge file to a partition which is mounted by NFS (Network File System). This issue will eat up all you network bandwidth until the copy process is finished, it can take an hour or more depending on the file size being copied.

This issue can be an ISSUE when it's a production server and your server is already over load, to copy a file you can use rsync command to limit your bandwidth and prevent network hogs:

rsync --bwlimit=1000 /var/www/html/ backups@server1.example.com:~/mysite

--bwlimit is in KB so the above example puts limit of 1000 Kilo Bytes on your copy command.

#rsync #bwlimit #NSF

There are times you run a command in cronjob in a specific interval. Let's say you run that command every hour.

If your command copies a huge file, or you are doing a heavy task that may take longer than 1 hour sometimes, then you need run-one
command in your arsenal.

run-one: run just one instance at a time of some command and unique set of arguments (useful for cronjobs, eg)


Sample run-one command:

run-one rsync -azP $HOME $USER@example.com:/srv/backup

See more samples here:
- http://manpages.ubuntu.com/manpages/xenial/man1/run-one.1.html


#linux #cronjob #command #run_one #runone

https://www.veeam.com/blog/the-3-2-1-0-rule-to-high-availability.html

#backup #backup_rules

https://www.hugeserver.com/kb/install-redis-4-debian-9-stretch/

#debian #redis #redis4

https://stackoverflow.com/questions/22163102/you-have-mail-message-in-terminal-os-x

#osx #mac #mail #iterm #terminal

https://github.com/m4ce/grafana-backup

#grafana #backup #python

tarfile is a python library to read and write gzip`/`bz2 compressed files.

How to read a gzip compressed tar archive and display some member information:

import tarfile
 tar = tarfile.open("sample.tar.gz", "r:gz")
 for tarinfo in tar:
     print tarinfo.name, "is", tarinfo.size, "bytes in size and is",
     if tarinfo.isreg():
         print "a regular file."
     elif tarinfo.isdir():
         print "a directory."
     else:
         print "something else."
 tar.close()

Create a compressed file:

with tarfile.open(dst, "w:gz") as tar:
     print("Archiving " + src + " into " + dst)
     tar.add(src, arcname = os.path.basename(src))

NOTE: the flag of w:gz opens the destination in write mode. Used to create a new tar file.

#python #tarfile #tar #bz2 #gzip

Linux in Docker: Wheezy: "ps: command not found"

Solution:

RUN apt-get update && apt-get install -y procps

#docker #linux #ps #command_not_found #procps

How to go to the previous working directory in terminal?

cd -

#linux #cd #last_working_directory

How do you delete all text above a certain line?

dgg

Will delete everything from your current line to the top of the file.

#vim #delete #dgg

How to check expiration time of a PEM certificate using openssl?

$ openssl x509 -enddate -noout -in file.pem
 notAfter=Sep  3 02:23:50 2018 GMT

#openssl #expiration_date

https://stackoverflow.com/questions/29479041/uwsgi-python-highload-configuration

#python #uwsgi #highload