How To get this script to run on your server - Bash Script - bash

#!/bin/bash
echo "Content-Type: image/gif"
echo
cat x.gif
OUTPUT=" $QUERY_STRING,$REMOTE_ADDR,$HTTP_USER_AGENT,$HTTP_REFERER,`date`"
echo $OUTPUT >> log.txt
sleep 2.5

You can try this:
save the script into some file, for example script.sh
go to the directory, where the file exists, like cd my_folder
change file mode to executable with command: chmod +x script.sh
run the file: ./script.sh
That should work for you.
I remember, once I was also looking for the answer on exactly the same question.

Related

How to echo a output of a shell script, outside the script

We have a shell script in the following location.
/opt/shellscript/test1.sh
Content of test1.sh file.
USERVALUES = P1321,testusername#example.com
USERVALUES1 ="$USERVALUES"
echo "Value of USERVALUES1 is $USERVALUES1"
We need to execute another script
/opt/shellscript/test2.sh
Content of the test2.sh file.
chmod +x /opt/shellscript/test1.sh
sh /opt/shellscript/test1.sh
echo "Value of USERVALUES1 from script test1.sh is $USERVALUES1"
We need to get the output as below.
Value of USERVALUES1 from script test1.sh is P1321,testusername#example.com
Could someone help on the same, how we can achieve this use case.
Edit test1.sh (remove spaces)
USERVALUES=P1321,testusername#example.com
USERVALUES1=$USERVALUES
echo "Value of USERVALUES1 is $USERVALUES1"
To fetch vars in test2.sh form test1.sh you need to:
source test1.sh
cat test2.sh
chmod +x /opt/shellscript/test1.sh
# source /opt/shellscript/test1.sh
. /opt/shellscript/test1.sh
sh /opt/shellscript/test1.sh
echo "Value of USERVALUES1 from script test1.sh is $USERVALUES1"
You can not access internal data of another process. The other process has to expose the data. Typically by writing the data to a file descriptor: standard output, a pipe or a temporary file.

bash: run multiple commands each separately with a command prompt

I want to run multiple commands like they are executed one at a time on command prompt
Eg i have the following list of commands
ls
pwd
du -sh
Now i try to copy paste them and run:
$ ls
pwd
du -sh
file1.txt file2.txt
/home/user/test
1M .
but instead i want to get them executed separately. So that i can see their outputs like below
$ ls
file1.txt file2.txt
$ pwd
/home/user/test
$ du -sh
1M .
So is it possible if i a have a list of commands to paste them in such a way that they can execute as if one per command prompt. Else the only option is paste one command at a time.
Generally i get a list of commands to get executed.
While pasting essentially works the way you describe, it may end up looking cosmetically wrong when the input (and its local echo) shows up while the shell is still busy executing the previous command.
You could instead feed the commands to bash -i, which will read and execute them in turn, showing the prompt:
$ mypaste() { x="$(cat)"; bash -i <<< "$x"; }
$ mypaste # Now paste some commands and hit ctrl-d
ls
pwd
whoami
^D
This results in:
you#yourdir $ ls
some files
you#yourdir $ pwd
/home/you/yourdir
you#yourdir $ whoami
you
you#yourdir $ exit
$
nano myscript.sh or your favorite editor and paste the following.
#!/bin/bash
ls
pwd
du -sh
make it executable with chmod +x myscript.sh and run the script with
./myscript.sh
You can run any bash commands and see outputs
Try each command separated by semicolon:
ls; pwd; du -sh;
This will make it batch of commands. Shell will execute one by one and you don't have to paste each command separately.
Hope this helps.
The answer from that other guy worked and I used a slightly modified version using heredoc.
I wanted to script a sequence of commands that show the prompt so I could copy/paste on different systems and show how to replicate a bug.
simple version
bash -i << 'EOF'
echo "command one"
echo "command two"
EOF
more commands and pretty output
bash -i << 'EOF' && echo -e '\e[1A\e[K==========================================='
unset PROMPT_COMMAND; PS1='command-sequence:$ ' ; clear ; echo "==========================================="
mkdir /tmp/demo-commands
echo "file contents" > /tmp/demo-commands/file
cd /tmp/demo-commands
pwd
ls
cat file
rm file
rm -r /tmp/demo-commands
EOF
I customize the prompt and use echo -e '\e[1A\e[K to replace the last line with a separator

Bash: exported variable not loaded in sh script

I have the following test.sh script:
#!/bin/sh
echo "MY_VARIABLE=$MY_VARIABLE"
Well, if I execute the following:
export MY_VARIABLE=SOMEVALUE
/bin/bash test.sh
it prints:
MY_VARIABLE=
Why the MY_VARIABLE is not read in the test.sh script?
You can reproduce the context here using the following script:
touch test.sh
chmod a+x test.sh
echo "#!/bin/sh" >> test.sh
echo "echo "MY_VARIABLE=$MY_VARIABLE"" >> test.sh
export MY_VARIABLE=something
/bin/bash test.sh
In your script to create the context, the line
echo "echo "MY_VARIABLE=$MY_VARIABLE"" >> test.sh
creates the following line in test.sh:
echo MY_VARIABLE=
if MY_VARIABLE was unset before. The expansion of $MY_VARIABLE is done in the shell that prepares your context.
If you use single quotes
echo 'echo "MY_VARIABLE=$MY_VARIABLE"' >> test.sh
the script test.sh contains the correct line
echo "MY_VARIABLE=$MY_VARIABLE"
and prints MY_VARIABLE=something as expected.
Everything works well but if you want your parent process to keep environment update, you must source your script:
source test.sh
Otherwise, changes will only have effect during the execution of your script.
You can consider it the same as sourcing your ~/.bashrc file.

Bash script - Run commands that correspond to the lines of a file

I have a file like this (text.txt):
ls -al
ps -au
export COP=5
clear
Each line corresponds at a command. In my script, I need to read each line and launch each command.
ps: I tried all these options and with all of them I have the same problem with the command "export". In the file there is "export COP=5", but after running the script, if I do echo $COP in the same terminal, no value is displayed
while IFS= read line; do eval $line; done < text.txt
Be careful about it, it's generally not advised to use eval as it's quite powerful and as easy to be abused.
However, if there is no risk of influence from unprivileged users on text.txt it should be ok.
cat test.txt | xargs -l1 bash -c '"$#"' echo
In order to avoid confusion I would simply rename the file from text.txt to text and add a shebang (e.g. #!/bin/bash) as the first line of the file. Make sure it is executable by calling chmod +x text. Afterwards you can execute it as expected.
$ cat text
#!/bin/bash
ls -al
ps -au
clear
$ chmod +x text
$ ./text

Issue with scheduling in Linux

I scheduled a script using at scheduler in linux.
The job ran fine but the echo statements which I had redirected to a file are no where to be found.
The at scheduling command is as follows:
at -f /app/data/scripts/func_test.sh >> /app/data/log/log.txt 2>&1 -v 09:50
Can anyone point out what is the issue with the above command.
I cannot see any echo statements from the script in the log.txt file
To include shell syntax like I/O redirection, you'll need to either fold it into your script, or pass the input to at via standard input, like so:
at -v 09:50 <<EOF
sh /app/data/scripts/func_test.sh >> /app/data/log/log.txt 2>&1
EOF
If func_test.sh is already executable, you can omit the sh from the beginning of the command; it's there to ensure that you are passing a valid command line to at.
You can also simply ensure that your script itself redirects all its output to a specific log file. As an example,
#!/bin/bash
echo foo
echo bar
becomes
#!/bin/bash
{
echo foo
echo bar
} >> /app/data/log/log.txt 2>&1
Then you can simply run your script with at using
at -f /app/data/scripts/func_test.sh -v 09:50
with no output redirection, because the script itself already redirects all its output to that file.

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