how to check sha256sum value consistent with the reference value of the files downloaded( or copied) from somewhere ?
1. usage of the command sha256sum
Usage: sha256sum [OPTION]... [FILE]...
Print or check SHA256 (256-bit) checksums.
With no FILE, or when FILE is -, read standard input.
-b, --binary read in binary mode
-c, --check read SHA256 sums from the FILEs and check them
--tag create a BSD-style checksum
-t, --text read in text mode (default)
Note: There is no difference between binary and text mode option on GNU system.
The following four options are useful only when verifying checksums:
--quiet don't print OK for each successfully verified file
--status don't output anything, status code shows success
--strict exit non-zero for improperly formatted checksum lines
-w, --warn warn about improperly formatted checksum lines
--help display this help and exit
--version output version information and exit
The sums are computed as described in FIPS-180-2. When checking, the input
should be a former output of this program. The default mode is to print
a line with checksum, a character indicating input mode ('*' for binary,
space for text), and name for each FILE.
GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
For complete documentation, run: info coreutils 'sha256sum invocation'
2. An Example
[biocodee@localhost Downloads]$ ls -al
total 136640
drwxr-xr-x. 2 biocodee biocodee 231 Dec 25 09:44 .
drwx------. 16 biocodee biocodee 4096 Dec 25 07:53 ..
-rw-r--r--. 1 biocodee biocodee 40212 Dec 20 11:16 container-selinux-2.107-3.el7.noarch.rpm
-rw-r--r--. 1 biocodee biocodee 36243572 Dec 20 10:55 docker-ce-18.03.0.ce-1.el7.centos.x86_64.rpm
-rw-rw-r--. 1 biocodee biocodee 103553755 Dec 25 07:12 Miniconda3-py38_4.10.3-Linux-x86_64.sh
-rw-rw-r--. 1 biocodee biocodee 65 Dec 25 07:53 Miniconda3-py38_4.10.3.sha256
-rw-r--r--. 1 biocodee biocodee 69596 Dec 20 11:23 pigz-2.3.3-1.el7.centos.x86_64.rpm
[biocodee@localhost Downloads]$ echo "$(cat Miniconda3-py38_4.10.3.sha256) Miniconda3-py38_4.10.3-Linux-x86_64.sh" | sha256sum --check
Miniconda3-py38_4.10.3-Linux-x86_64.sh: OK
[biocodee@localhost Downloads]$ echo "$(cat Miniconda3-py38_4.10.3.sha256) container-selinux-2.107-3.el7.noarch.rpm" | sha256sum --check
container-selinux-2.107-3.el7.noarch.rpm: FAILED
sha256sum: WARNING: 1 computed checksum did NOT match
[biocodee@localhost Downloads]$ cat Miniconda3-py38_4.10.3.sha256
935d72deb16e42739d69644977290395561b7a6db059b316958d97939e9bdf3d
[biocodee@localhost Downloads]$ echo "935d72deb16e42739d69644977290395561b7a6db059b316958d97939e9bdf3d Miniconda3-py38_4.10.3-Linux-x86_64.sh" | sha256sum --check
Miniconda3-py38_4.10.3-Linux-x86_64.sh: OK
