Bash commands (chapters)

apt

2024-03-19 2023-01-12
apt HowTo's
2024-02-09 2009-05-29
apt-get / apt
dist-upgrade, download, GPG, recommends, sources.list, uninstalled
2024-01-16 2017-01-05
apt errors
2023-06-02 2018-10-23
apt-key
2020-03-25 2018-01-24
apt-cache
pkgnames

apt errors

2024-01-16
apt-key : Warning: apt-key is deprecated. Manage keyring files in trusted.gpg.d instead (see apt-key(8)).
2024-01-16 2023-01-03
apt update error : Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg),
2023-05-16 2017-01-05
apt update error : 407 Proxy Authentication Required
2023-01-12 2019-05-13
apt upgrade displays The following packages have been kept back:
2020-11-25
apt update error : Release file for http://deb.debian.org//InRelease is not valid yet Updates for this repository will not be applied.
2020-04-01
apt update error : Release file for http://ftp.fr.debian.org//InRelease is expired. Updates for this repository will not be applied.

apt HowTo's

2024-03-19 2023-01-12
How to prevent a package from being updated ? hold it !
2023-08-04
How to reinstall some package configuration files ?
2023-08-04
How to restore a file to its fresh install state ?
2023-05-16
How to configure a proxy for apt ?

avconv

2020-11-11
How to mix an audio + a video track ?
2019-01-31 2018-04-19
How to concatenate audio / video files ?
2019-01-31 2017-12-27
How to convert audio files ?
flac, mp3, wav
2018-10-07 2016-11-09
avconv
2017-09-12 2013-05-20
How to extract the audio track from a movie ?
bitrate, ffmpeg, mp3, ogg, wav
2016-11-23 2016-09-18
How to trim audio or video files ?
cut
2016-09-04
How to re-order the audio tracks of a .mkv file ?
2016-09-04 2014-01-26
How to convert video files ?
mkv, mpeg

Awk

2023-12-18 2018-05-22
Awk commands
2023-07-31 2017-01-30
Awk HowTo's
2023-07-31 2003-02-14
awk
2023-04-17 2022-01-07
Awk examples
2023-02-22 2016-07-04
Awk internal variables
$n FILENAME FS NF NR OFS RS
2019-10-11 2018-10-16
Awk internal keywords
BEGIN BEGINFILE END ENDFILE next
2018-12-06
Make music with awk
2017-07-25
awk vs gawk
2017-02-02 2012-12-11
Tailor files / strings / substrings with Awk / Bash / PERL / sed
RegExp

Awk commands

2023-12-18 2018-05-22
system
2023-09-14 2022-06-17
if else
2023-04-17 2019-10-11
next
2023-04-17
exit
2023-04-17
break
2019-06-14 2019-03-27
print, printf, sprintf
2019-06-07
print
2019-03-04
switch case

Awk HowTo's

2023-07-31
Is it possible to alter files inplace with awk like sed -i does ?
2022-09-06 2018-04-24
How to filter fields to print ?
2022-01-07 2019-09-27
Awk : how to alter fields with gsub ?
2019-12-17 2019-12-12
Awk : how to alter fields with gensub ?
2019-10-11
Awk : how to detect the last line of input ?
2018-12-11
How to return a different exit code stating match found / match not found ?
2017-07-18
How to use another character instead of / as the regular expression delimiter ?
2017-01-30
How to customize the display of data fields ?
for, NF, printf

cURL

2023-09-14 2018-03-20
cURL errors
2023-09-13
Inspecting HTTP response headers
HTTP/1.1 HTTP/2
2022-02-21 2012-02-07
curl
credentials, head, get, post, put, user agent, Unsupported proxy scheme
2021-09-07
cURL : how to ignore / bypass the current proxy settings ?
~/.curlrc, http_proxy, --noproxy

htop

2023-10-02
How to follow a process with htop ?
2021-02-09 2013-06-25
htop
VIRT, RES, SHR

cURL errors

2023-09-14
curl -I : why do I see 2 blocks of HTTP headers ?
2023-02-08
curl: (35) error:0A00010B:SSL routines::wrong version number
2020-10-14
TLSv1.2 (IN), TLS alert, close notify (256):
2020-10-14
Expire in 0 ms for 1 (transfer 0x559d3dcc1bb0)
2019-11-05 2018-03-01
curl: (52) Empty reply from server
2019-05-15 2019-04-11
curl: (35) error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol
~/.curlrc
2018-03-21
What does additional stuff not fine transfer.c:1037: 0 0 mean ?
2018-03-20
curl: (56) Recv failure: Connection reset by peer
2018-03-20
curl: (7) Unsupported proxy scheme for 'https://login:password@proxy.company.tld:port'

mount

2024-03-12 2021-09-21
mount error(127): Key has expired or mount(2) system call failed: Key has expired
2022-08-26
mount error(111): could not connect to 192.168.1.8Unable to find suitable address.
2021-01-24 2013-01-08
mount

nmap

2024-03-08 2009-09-21
nmap
2018-09-14
How to enumerate the subdomains of a domain ?
2015-06-12
Nmap complains : route_dst_netlink: can't find interface "venet0"

nmcli

2024-04-10 2024-03-07
How to delete a connection ?
2024-03-25
How to declare / update DNS resolvers ?
2024-03-25 2024-03-04
nmcli
2024-03-25 2024-03-07
How to view details of a connection ?
2024-03-18 2024-03-07
How to list connections and retrieve a connection name ?
2024-03-07
How to change the IP address of a connection ?

OpenSSL

2023-10-06 2018-03-21
How to get certificate metadata ?
validity date range, issuer, purpose, subject
2023-09-28 2023-01-12
OpenSSL commands
2023-06-23 2013-07-03
openssl
starttls
2018-03-22
openssl errors
2018-03-21
How to test an SSL / TLS connection as a client ?

OpenSSL commands

rsync

2023-07-10 2013-09-20
rsync errors
2023-07-04 2013-09-20
rsync
2020-06-03
Rsync : notes about backups
2020-06-03 2013-09-20
Rsync can delete millions of files quicker than rm and find

rsync errors

2023-07-10
rsync: failed to set times on "/path/to/file": Operation not permitted (1)
2022-01-27
rsync: [generator] symlink failed: Operation not supported (95)
2021-03-11
rsync: failed to set permissions on "/path/to/file": Operation not permitted
2020-05-04
skipping directory .
2019-01-10
Error reading response length from authentication socket.
2019-01-10 2013-09-20
protocol version mismatch -- is your shell clean?
2019-01-10 2013-09-20
Unexpected remote arg
2019-01-10 2013-09-20
ksh: rsync: not found when trying to rsync files between a Linux and a Solaris machine

GNU screen

2023-01-11 2020-01-28
GNU Screen hotkeys
2022-04-12 2020-12-02
How to change the number of a GNU screen window (i.e. move it) ?
2022-04-04 2010-03-05
screen
.screenrc, bind, split
2020-11-10
How to free the Ctrl-a key sequence for Emacs ?
2020-09-17 2010-03-05
How to copy text from a Screen session ?
2020-09-11
How to use variables in .screnrc ?
2020-04-06 2017-09-28
Screen : how to bind a function to a key ?
.screenrc
2017-07-07
Is it possible to pre-populate Screen windows ?
.screenrc
2017-01-23
How to get / set the scrollback value ?
2016-12-19
How to change the Screen window settings : color, background color ?
2016-12-13
How to detect whether the current shell is executed within a Screen ?
2016-11-04
How to get / set the Screen window title from the shell ?
2010-03-05
How to work in split-screen mode ?
2010-03-05
What if I can not completely detach a session then re-attach it ?
2010-03-05
Cannot open your terminal '/dev/pts/11' - please check.
2010-03-05
How to share a Screen session ?

sed

2023-10-27 2010-09-27
sed
2021-01-14
sed branching
2019-07-12 2010-09-27
How to chain sed commands ?
2018-12-07 2010-09-27
Need a RegExp "lazy star" ?
2016-01-28 2010-09-27
Extract fields from a logfile
2016-01-28 2010-09-27
Count the number of articles in this file with anchor starting with each alphabet letter

SSH

2024-01-23 2012-03-22
ssh
2022-11-24 2018-08-27
ssh-keygen
2020-03-26 2018-04-25
ssh-copy-id

su

2023-06-27
How to use su non-interactively ?
2022-05-18 2015-08-07
su
This account is currently not available.

sudo

2024-02-27
What's the difference between sudo -i and sudo su - ?
2024-02-09 2022-10-11
Is it mandatory that /etc/sudoers.d/filename matches username ?
2022-10-11 2009-08-06
How to become a sudoer ?
2022-08-01
sudo vs ssh root
2020-10-22 2013-05-02
sudo
2020-03-30
How to open a shell as an other user whose login shell is disabled ?
2015-11-03
How to login as root via sudo only ?

systemctl

2024-03-12 2017-09-07
systemctl
2024-03-12
systemctl daemon-reload
2020-03-04
systemctl status myApplication returns Active: failed (Result: start-limit-hit)

xargs

2022-09-21 2013-03-13
xargs
123
2022-02-12
xargs: unmatched single quote; by default quotes are special to xargs unless you use the -0 option

youtube-dl

2023-08-27 2016-10-09
youtube-dl
2022-08-29 2017-07-06
How to download an album / playlist from YouTube with the best possible audio quality (no format conversion) ?
2020-02-05 2019-01-31
What if the best quality audio and video tracks are in distinct YouTube streams ?
2018-04-19 2017-06-21
How to download a track / playlist from YouTube and convert it to MP3 ?
2017-07-06 2016-10-09
How to download a single song / video from YouTube ?

yum

2022-09-22
How to update all packages to their latest version ?
2021-03-16 2011-07-11
yum
2020-04-02
yum error : [Errno 14] HTTPS Error 403 - Forbidden