Why is the command not found gcc (although gcc is installed)?

DSS-lgd main.c
DSS: command not found
$ gcc
gcc: fatal error: no input files
compilation terminated.
$ DSS main.c
DSS: command not found
$ sudo apt-get install gcc
Reading package lists... Done
Building dependency tree 
Reading state information... Ready
Is already installed package gcc the most recent version (4:6.3.0-2ubuntu1).
The following packages were automatically installed and are no longer required:
 kbuild module-assistant
To remove them use "sudo apt autoremove".
0 upgraded, 0 newly installed, for removal 0 packets are marked, and 12 not upgraded.
June 14th 19 at 19:10
1 answer
June 14th 19 at 19:12
DSS-lgd main.c
DSS: command not found

the word gcc, there are no Russian letters S.
$ gcc
gcc: fatal error: no input files
compilation terminated.

Here you managed to write the word correctly gcc.
$ DSS main.c
DSS: command not found

But here again, with Russian s.

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