dos – If not exists then exit cmd – Stack Overflow

You have two ways:

Lets start by looking for a specific application in my laptop:

[root@pinky:~]# ps fax | grep mozilla
 3358 ?        S      0:00  _ /bin/sh /usr/lib/firefox-3.5/run-mozilla.sh /usr/lib/firefox-3.5/firefox
16198 pts/2    S      0:00              _ grep mozilla

All examples now will look for PID 3358.

First way: Run “ps aux” and grep for the PID in the second column. In this example I look for firefox, and then for it’s PID:

[root@pinky:~]# ps aux | awk '{print $2 }' | grep 3358
3358

So your code will be:

if [ ps aux | awk '{print $2 }' | grep -q $PID 2> /dev/null ]; then
    kill $PID 
fi

Second way: Just look for something in the /proc/$PID directory. I am using “exe” in this example, but you can use anything else.

[root@pinky:~]# ls -l /proc/3358/exe 
lrwxrwxrwx. 1 elcuco elcuco 0 2021-06-15 12:33 /proc/3358/exe -> /bin/bash

So your code will be:

if [ -f /proc/$PID/exe ]; then
    kill $PID 
fi

BTW: whats wrong with kill -9 $PID || true ?

EDIT:

After thinking about it for a few months.. (about 24…) the original idea I gave here is a nice hack, but highly unportable. While it teaches a few implementation details of Linux, it will fail to work on Mac, Solaris or *BSD. It may even fail on future Linux kernels. Please – use “ps” as described in other responses.

I want to make sure node is running when logging in. So in my .bashrc file I have:

pkill node
sleep 1
node server.js &

Of course, that doesn’t check if node is running… it simply kills it and starts it up again. Instead I’d like something like this:

node_process = $(pidof node)
if [not_exists node_process]; then
  node server.js &
fi

The problem is the not_exists method doesn’t seem to exist :). How do I test the existence of a number or string in Bash and is this the best way to ensure node is up and running upon login?

Here is a good example on how to do a command if a file does or does not exist:

if exist C:myprogramsyncdata.handler echo Now Exiting && Exit
if not exist C:myprogramhtmldata.sql Exit

We will take those three files and put it in a temporary place. After deleting the folder, it will restore those three files.

xcopy "test" "C:temp"
xcopy "test2" "C:temp"
del C:myprogramsync
xcopy "C:temp" "test"
xcopy "C:temp" "test2"
del "c:temp"

Use the XCOPY command:

xcopy "C:myprogramhtmldata.sql"  /c /d /h /e /i /y  "C:myprogramsync"

I will explain what the /c /d /h /e /i /y means:

  /C           Continues copying even if errors occur.
  /D:m-d-y     Copies files changed on or after the specified date.
               If no date is given, copies only those files whose
               source time is newer than the destination time.
  /H           Copies hidden and system files also.
  /E           Copies directories and subdirectories, including empty ones.
               Same as /S /E. May be used to modify /T.
  /T           Creates directory structure, but does not copy files. Does not
               include empty directories or subdirectories. /T /E includes
  /I           If destination does not exist and copying more than one file,
               assumes that destination must be a directory.
  /Y           Suppresses prompting to confirm you want to overwrite an
               existing destination file.

`To see all the commands type`xcopy /? in cmd

Call other batch file with option sync.bat myprogram.ini.

I am not sure what you mean by this, but if you just want to open both of these files you just put the path of the file like

Path/sync.bat
Path/myprogram.ini

If it was in the Bash environment it was easy for me, but I do not
know how to test if a file or folder exists and if it is a file or
folder.

You are using a batch file. You mentioned earlier you have to create a .bat file to use this:

I have to create a .BAT file that does this:

exit is a key word in DOS/Command Prompt – that’s why goto exit
doesn’t work.

Using if not exist “file name” exit dumps you out of that batch file.
That’s fine if exiting the batch file is what you want.

If you want to execute some other instructions before you exit, change the label to something like :notfound then you can goto notfound
and execute some other instructions before you exit.

(this is just a clarification to one of the examples)