how to change permissions in linux for a file code example

Example 1: debian give write permission

sudo chmod -R 757 /var/www

Example 2: change mode in linux

For changing permissions mode of files as "file.exe" follow next examples idea:
chmod file.exe ugo+x #Add x:execute permissions to u:user g:gropu and o:others
chmod file.exe o-rw  #Remove r:read and w:write permissions to o:others
chmod file.exe +rwx  #Add all r:read, w:wirte and x:execute permissions to all.

Example 3: how to set execute permission in linux

chmod -x script-name-here.sh #Change the "script-name-here" to the name of your .sh file.