do-release-upgrade
Checking for a new Ubuntu release
There is no development version of an LTS available.Package manager conf file:/etc/apt/sources.list dosyası şöyledir
Each PM has its own conf file associated with it which contains the location of all repos i.e repositories that contain the packages. The conf file contains the location of all official repos . Packages are also present on third parties repos so you can edit the location of these packages in the conf file. But you have to take care of the security issue. The default conf file present on the ubuntu system is “/etc/apt/sources”. So using this conf file PM knows where exactly the packages are present.
deb http://deb.debian.org/debian jessie main
...# cat /etc/apt/sources.list
# Repos managed by puppet.
deb [signed-by=/usr/share/keyrings/hazelcast-archive-keyring.gpg] https://repository.hazelcast.com/debian stable mainSoftware Settings -> Software & Updates -> Other Softwarels -l `which apt-add-repository`
... /usr/bin/apt-add-repository -> add-apt-repositorysudo add-apt-repository universe
sudo apt-get update
sudo apt install blender steamsudo apt-add-repository universe
sudo apt-get update
sudo apt-get install wireguardsudo add-apt-repository ppa:ubuntu-desktop/ubuntu-make
sudo apt-get update
sudo apt-get install ubuntu-makesudo add-apt-repository ppa:tista/adapta
sudo apt-get update
sudo apt-get install adapta-gtk-themesudo apt update
...
Err:9 http://ppa.launchpad.net/wireguard/wireguard/ubuntu focal InRelease
403 Forbidden [IP: 91.189.95.83 80]
Reading package lists... Done
E: Failed to fetch http://ppa.launchpad.net/wireguard/wireguard/ubuntu/dists
/focal/InRelease 403 Forbidden [IP: 91.189.95.83 80]
E: The repository 'http://ppa.launchpad.net/wireguard/wireguard/ubuntu focal
InRelease' is no longer signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by
default.
N: See apt-secure(8) manpage for repository creation and user configuration details.sudo apt-add-repository -r ppa:wireguard/wireguardIn other words, the default behavior for cd foo is "move into the directory named 'foo' which is a subdirectory of the current directory or of any other directory that is given in CDPATH". When CDPATH is not set, cd will only look in the current directory but, when it is set, it will also look for a match in any of the directories you set it to.Değer Atama
CDPATH="/path/to/dir1:/path/to/dir2:/path/to/dirN"$ echo $CDPATH ## CDPATH is not set
$ cd etc ## fails: there is no "etc" directory here
bash: cd: etc: No such file or directory
$ CDPATH="/" ##CDPATH is now set to /
$ cd etc ## This now moves us to /etc
/etcELF object file starts with 0x7F 0x45 0x4C 0x46 (with bytes 2-4 being 'ELF' in ASCII).Shebang Magic Number
The kernel opens the executable, and finds that it starts with #!.Bir elf dosyasının başlığını görmek için şöyle yaparız.
The kernel closes the executable and opens the interpreter instead.
The kernel inserts the path to the script to the argument list (as argv[1]), and executes the interpreter.
$ readelf -a MyApptypedef struct {
uint8 e_ident[16];
uint16 e_type;
uint16 e_machine;
uint32 e_version;
uint32 e_entry;
uint32 e_phoff;
uint32 e_shoff;
uint32 e_flags;
uint16 e_ehsize;
uint16 e_phentsize;
uint16 e_phnum;
uint16 e_shentsize;
uint16 e_shnum;
uint16 e_shstrndx;
} Elf32Hdr;// check so its really an elf file
if(header.e_ident[0] == 0x7f &&
header.e_ident[1] == 'E' &&
header.e_ident[2] == 'L' &&
header.e_ident[3] == 'F') {...}This byte is set to either 1 or 2 to signify little or big endianness, respectively. This affects interpretation of multi-byte fields starting with offset 0x10.Görmek için şöyle yaparız. Aşağıdaki örnekte LSB çıktısını görürüz. Uygulam little endian'dır.
$ file /bin/ls
/bin/ls: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked,
interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32,
BuildID[sha1]=4637713da6cd9aa30d1528471c930f88a39045ff, strippedNAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 931.5G 0 disk
├─sda1 8:1 0 100M 0 part
└─sda2 8:2 0 931.4G 0 part
sdb 8:16 1 14.4G 0 disk
├─sdb1 8:17 1 42.9M 0 part /media/ubuntu/boot
└─sdb2 8:18 1 14.4G 0 part /media/ubuntu/rootfs
sdc 8:32 1 59.7G 0 disk
├─sdc1 8:33 1 256M 0 part /media/ubuntu/boot1
└─sdc2 8:34 1 59.4G 0 part /media/ubuntu/rootfs1
sr0 11:0 1 2G 0 rom /cdromcp -pr /media/ubuntu/rootfs/max7219 /media/ubuntu/rootfs1/NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTsize Sütunu Ne Demek
sda 8:0 0 931,5G 0 disk
├─sda1 8:1 0 487M 0 part /boot/efi
├─sda2 8:2 0 925,3G 0 part /
└─sda3 8:3 0 5,7G 0 part [SWAP]
sr0 11:0 1 1024M 0 rom
$ lsblk -b
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 34359738368 0 disk
├─xvda1 202:1 0 1676673024 0 part [SWAP]
└─xvda2 202:2 0 32682016768 0 part /var/spool-e, --exclude list
Exclude the devices specified by the comma-separated list of
major device numbers. Note that RAM disks (major=1) are
excluded by default. The filter is applied to the top-level
devices only.$ lsblk -e7
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 238.5G 0 disk
├─sda1 8:1 0 9.8G 0 part
├─sda2 8:2 0 164.7G 0 part
├─sda3 8:3 0 31.1G 0 part /
├─sda4 8:4 0 1K 0 part
├─sda5 8:5 0 15.3G 0 part /usr/local
└─sda6 8:6 0 17.7G 0 part /home
sr0 11:0 1 1024M 0 rom.. df -h and lsblk -f display disk usage/remaining disk space for mounted partitionsÖrnek
xubuntu@xubuntu:~$ lsblk -f
NAME FSTYPE LABEL UUID FSAVAIL FSUSE% MOUNTPOINT
loop0 iso9660 Xubuntu 20.04 LTS amd64 2020-04-23-07-50-17-00 0 100% /cdrom
loop1 squashfs 0 100% /rofs
sda
├─sda1 ext4 bionic 2093f8d6-7840-4256-8edc-4db97e865784 12.2G 87% /media/xubuntu/bionic
├─sda2 swap 4b882c9f-4867-4c5c-8eb7-c84ef03f4786 [SWAP]
└─sda3 ext4 focal 31f64dfc-933a-4f48-9209-e7a7b016d8c9
sdb
├─sdb1
├─sdb2 vfat usbboot 02D3-7915
└─sdb3 ext4 isodevice 04d5aa8c-aa1e-4a71-9d79-edaf6e8b2111 7.7G 16% /isodevice
sr0
xubuntu@xubuntu:~$ NAME TRAN
sda sata
└─sda1
sdb usb
sr0 satalsblk -l -o name,tranÇıktı olarak şunu alırız
NAME TRAN
sda sata
sda1
sdb usb
sdc usb
sr0 sata$ sudo lsblk -o NAME,LABEL
NAME LABEL
sda
├─sda1 System Reserved
├─sda2
├─sda3
├─sda5
└─sda6$ lsblk -o NAME,FSTYPE,LABEL,MOUNTPOINT,SIZE,MODELln source targetln [option]… [-T] target linknameln sourcefile hardlinkfileOne way to compute hash values is using openssl. You can give it a file as an argument, or pipe a string to it.list seçeneği
To see the list of hash functions openssl supports, use list --digest-commands.Örnek
$ openssl list --digest-commands
blake2b512 blake2s256 gost md4
md5 mdc2 rmd160 sha1
sha224 sha256 sha3-224 sha3-256
sha3-384 sha3-512 sha384 sha512
sha512-224 sha512-256 shake128 shake256
sm3
echo hello | sha1sum
f572d396fae9206628714fb2ce00f72e94f2258f -openssl dgst -sha256 myfileecho -n 'hello world' | openssl dgst -sha256
b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9openssl dgst -sha256 -binary <<<"..."