It seems that newer versions of bash have the &> operator, which (if I understand correctly), redirects both stdout and stderr to a file (&>> appends to the file instead, as Adrian clarified). What’s the simplest way to achieve the same thing, but instead piping to another command? For example, in this line: cmd-doesnt-respect-difference-between-stdout-and-stderr | … Read more
Let’s say I have a script like the following: useless.sh echo “This Is Error” 1>&2 echo “This Is Output” And I have another shell script: alsoUseless.sh ./useless.sh | sed ‘s/Output/Useless/’ I want to capture “This Is Error”, or any other stderr from useless.sh, into a variable. Let’s call it ERROR. Notice that I am using … Read more
I am rather confused with the purpose of these three files. If my understanding is correct, stdin is the file in which a program writes into its requests to run a task in the process, stdout is the file into which the kernel writes its output and the process requesting it accesses the information from, … Read more
This question already has answers here: How to redirect and append both standard output and standard error to a file with Bash (9 answers) Closed 5 years ago. I am running a bash script that creates a log file for the execution of the command I use the following Command1 >> log_file Command2 >> log_file … Read more
This question already has answers here: How to redirect and append both standard output and standard error to a file with Bash (9 answers) Closed 8 months ago. I want to redirect both standard output and standard error of a process to a single file. How do I do that in Bash? 15 s 15 … Read more
I have a program that writes information to stdout and stderr, and I need to process the stderr with grep, leaving stdout aside. Using a temporary file, one could do it in two steps: command > /dev/null 2> temp.file grep ‘something’ temp.file But how can this be achieved without temp files, using one command and … Read more
To redirect standard output to a truncated file in Bash, I know to use: cmd > file.txt To redirect standard output in Bash, appending to a file, I know to use: cmd >> file.txt To redirect both standard output and standard error to a truncated file, I know to use: cmd &> file.txt How do … Read more
There are several ways to write to stderr: # Note: this first one does not work in Python 3 print >> sys.stderr, “spam” sys.stderr.write(“spam\n”) os.write(2, b”spam\n”) from __future__ import print_function print(“spam”, file=sys.stderr) That seems to contradict zen of Python #13 †, so what’s the difference here and are there any advantages or disadvantages to one … Read more
