Shell Script cannot find python3.6 interpreter

Question

I have a file called update.sh which looks like this:

#!/bin/sh

python3.6

When this file is located in /bin directory it works and python3.6 starts like this:

Python 3.6.7 (default, Oct 22 2018, 11:32:17)
[GCC 8.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>

But when this file update.sh is any other directory like where my other projects files are the same file gives error like this:

: not found./update.sh: python3.6

And any other commands like cd, ls also only work in the /bin directory and not in any other.

What is wrong and how to fix this?

running printenv in my projects folder returns this:

NVM_DIR=/home/cosmicsage/.nvm
LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.zst=01;31:*.tzst=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.wim=01;31:*.swm=01;31:*.dwm=01;31:*.esd=01;31:*.jpg=01;35:*.jpeg=01;35:*.mjpg=01;35:*.mjpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.m4a=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.oga=00;36:*.opus=00;36:*.spx=00;36:*.xspf=00;36:
HOSTTYPE=x86_64
LESSCLOSE=/usr/bin/lesspipe %s %s
LANG=C.UTF-8
OLDPWD=/mnt/d/Projects/web-engine
NVM_CD_FLAGS=
USER=cosmicsage
PWD=/mnt/d/Projects/web-engine/.git/hooks
HOME=/home/cosmicsage
NAME=DarkPlayground
XDG_DATA_DIRS=/usr/local/share:/usr/share:/var/lib/snapd/desktop
SHELL=/bin/bash
TERM=xterm-256color
NVM_BIN=/home/cosmicsage/.nvm/versions/node/v11.7.0/bin
SHLVL=1
LOGNAME=cosmicsage
PATH=/home/cosmicsage/.local/bin:/home/cosmicsage/.nvm/versions/node/v11.7.0/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/mnt/c/Program Files/WindowsApps/CanonicalGroupLimited.Ubuntu18.04onWindows_1804.2019.522.0_x64__79rhkp1fndgsc:/mnt/c/Program Files (x86)/Intel/Intel(R) Management Engine Components/iCLS:/mnt/c/Program Files/Intel/Intel(R) Management Engine Components/iCLS:/mnt/c/Windows/System32:/mnt/c/Windows:/mnt/c/Windows/System32/wbem:/mnt/c/Windows/System32/WindowsPowerShell/v1.0:/mnt/c/Program Files (x86)/Intel/Intel(R) Management Engine Components/DAL:/mnt/c/Program Files/Intel/Intel(R) Management Engine Components/DAL:/mnt/c/Program Files (x86)/Intel/Intel(R) Management Engine Components/IPT:/mnt/c/Program Files/Intel/Intel(R) Management Engine Components/IPT:/mnt/c/Program Files (x86)/NVIDIA Corporation/PhysX/Common:/mnt/c/Windows/System32:/mnt/c/Windows:/mnt/c/Windows/System32/wbem:/mnt/c/Windows/System32/WindowsPowerShell/v1.0:/mnt/c/Program Files/NVIDIA Corporation/NVIDIA NvDLISR:/mnt/c/Windows/System32/OpenSSH:/mnt/c/Users/admin/AppData/Local/Microsoft/WindowsApps:/mnt/c/Users/admin/AppData/Local/Microsoft/WindowsApps:/mnt/c/Users/admin/AppData/Local/atom/bin:/snap/bin
LESSOPEN=| /usr/bin/lesspipe %s
_=/usr/bin/printenv

I've tried setting the $PATH variable but I don't think I know how to do it correctly.

I'm also running UBUNTU 18.04 ON WSL.

Even if I change the shebang to #!/usr/bin/env bash or other doesn`t solve the problem either.

Answer 1

The problem was in the line-endings for me

My script looked like this:

#!/bin/sh

python3.6

On close inspection of this file in the atom text-editor I found the the line-endings to be "CRLF"(WINDOWS)

I Then changed the line-endings to be "LF"(LINUX) AND the script was executed!!!

Conclusion: The error was caused by the line-endings as pointed in the comments by @glennjackman . Change it to LF in atom