How to solve ambiguous redirect?

Adding quotes around the variable seems to be a good way to deal with the “ambiguous redirect” message: You tend to get a better message when you’ve made a typing mistake — and when the error is due to spaces in the filename, using quotes is the fix.

What is ambiguous output redirect?

The “ambiguous redirect” error sometimes happens if you either have spaces where they shouldn’t be, or conversely when an important space is missing. I would simplify your command to demonstrate: echo “Test” >/tmp/x.txt 2>&1 & The “>/tmp/x. txt” part will redirect stdout (file handle #1).

How do I redirect in Bash?

In general you can write command n>file , which will redirect the file descriptor n to file . Redirects the output of the ls command to the file_list file. Here bash redirects the stderr to file. The number 2 stands for stderr.

What is bad substitution in shell script?

Bad Substitution Error Related to Command Substitution One circumstance in which this error occurs is when you want to use command substitution but by mistake you use curly braces instead of parentheses. Command substitution allows to store the output of a Bash command (as complex as you want) into a variable.

How do you set a variable in Bash?

The easiest way to set environment variables in Bash is to use the “export” keyword followed by the variable name, an equal sign and the value to be assigned to the environment variable.

How do I append to a file in Bash?

To make a new file in Bash, you normally use > for redirection, but to append to an existing file, you would use >> . Take a look at the examples below to see how it works. To append some text to the end of a file, you can use echo and redirect the output to be appended to a file.

How do I redirect a null output in Linux?

You can send output to /dev/null, by using command >/dev/null syntax. However, this will not work when command will use the standard error (FD # 2). So you need to modify >/dev/null as follows to redirect both output and errors to /dev/null.

How do you redirect output?

On a command line, redirection is the process of using the input/output of a file or command to use it as an input for another file. It is similar but different from pipes, as it allows reading/writing from files instead of only commands. Redirection can be done by using the operators > and >> .

How do I redirect standard error in bash?

2> is input redirection symbol and syntax is:

  1. To redirect stderr (standard error) to a file: command 2> errors.txt.
  2. Let us redirect both stderr and stdout (standard output): command &> output.txt.
  3. Finally, we can redirect stdout to a file named myoutput.txt, and then redirect stderr to stdout using 2>&1 (errors.txt):

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