This question already has answers here:
Bash script - variable content as a command to run
(7 answers)
Closed 1 year ago.
So I have a command that's like
cmd1|cmd2|...|cmdN|execute
The output of cmdN is one line that I want execute to execute as if I copy pasted the output of cmdN into the terminal myself. I've tried to replace execute with bash, with $, and I tried to use xargs. (I'm still kinda confused on each of the options I've tried).
What's the simple answer here that's gonna make me wanna delete this post?
If you need to execute it in the current shell, use the eval command:
eval "$(cmd1|cmd2|...|cmdN)"
If it can be executed in a subshell, pipe to bash:
cmd1|cmd2|...|cmdN | bash
Related
This question already has answers here:
Difference between sh and Bash
(11 answers)
Closed 2 years ago.
"paste -d'|' <(echo 22)
the code is righ in command line , but I wrote it to a shell file , it's error.
this result :
How to resolve this!
Thinks!
#!/bin/bash informs the shell to use bash, and when you run it with sh it does not use bash as sh is forced.
sh is way more limited than bash, so if your script uses bash logic, but is run via sh, it is not fully compatible, and errors out where sh does not understand the commands.
This question already has answers here:
Can I export a variable to the environment from a Bash script without sourcing it?
(13 answers)
Closed 3 years ago.
I have created a virtual environment on my debian system and i made a script that activates it (should).
However when i execute the script nothing shows up, not even an error, my guess is that it is running in a different shell or something but I don't know how to solve it.
Here is the code of the script
#!/bin/bash
source ~/PythonEnv/environments/my_env/bin/activate
I have changed the permissions already with chmod u+x, so that is not a problem.
When i execute the script nothing shows up at all. Any thoughts???
Add set -x at the beginning of your bash script will do the trick.
-x Print commands and their arguments as they are executed.
You can see more bash options here
http://linuxcommand.org/lc3_man_pages/seth.html
Adding x-permissions is not necessary, since you are using source with an absolute path. Of course this sets the environment only which is executed by the shell script which you have posted here. If you want the changes in your interactive shell, it is pointless to do it inside a script. You have to source the activate script in your shell (respectively inside that process where you want the environment to be modified).
This question already has answers here:
What is the difference between $(command) and `command` in shell programming?
(6 answers)
Closed 4 years ago.
Hi I am trying to print the public ip of the machine in a file using shell script. I am using the command
ip=${curl ipinfo.io/ip}
in my script file and it gives an error saying bad substitution. whereas this command works when i run it in command line.
Is this the right way to get the ip through the script?
Thanks in advance!!
You are capturing the result of program so you should use $(). The following should work for you (with the -s parameter to curl stopping unnecessary output)
ip=$(curl -s ipinfo.io/ip)
This question already has answers here:
What does it mean in shell when we put a command inside dollar sign and parentheses: $(command)
(2 answers)
Closed 3 years ago.
I run following command in Linux terminal. Can anyone tell me what is the use of parentheses in Linux terminal and following command also ?
$(echo "GET / HTTP/1.0";echo "Host: www.google.com"; echo) | nc www.google.com 80
( list )
Placing a list of commands between parentheses causes a subshell environment to be created, and each of the commands in list to be executed in that subshell. Since the list is executed in a subshell, variable assignments do not remain in effect after the subshell completes.
Parentheses denote a subshell in bash. In your command, the $() is command substitution and if it is like () is a subshell. Both of them run commands, the difference is what happens to the output.
Unix & Linux Answer
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Capturing multiple line output to a bash variable
For example I want to run ls command and take the return list as a value kept in a array in shell script.
Something like
run
#ls
fileA
fileB
fileC
kept this return list in a variable that keeps a array
variable A = ["fileA","fileB","fileC"];
I cannot give the exact notation for code since I do not know how to write shell script. After I learn this, I 'll.
#!/bin/bash
variableA=$(ls)
echo $variableA
That should be your shell script assuming that you have bash
Then all you'd need to do is chmod +x shell_script to make it executable.
If you use ls > contents.file the result of ls is saved to a file called contents.file.
Remember, > rewrites the entire file while >> appends to the last line.
variableA=$(ls)
echo "$variableA"