31 Unix Streams, Pipes, Scripts

31.1 Unix Streams, Pipes, Scripts

Here’s a recording of this lecture (53 minutes 54 seconds):

31.2 Unix Basics slides

31.3 Questions

31.3.1 Question 1

Which of the following statements about typing commands into the terminal is correct?

By default, output (stdout and stderr) goes to the screen. You can pipe it to files with the | operator. By default, output (stdout and sdterr) goes to a log file, unless you redirect them to the screen. By default, stdout goes to the screen and stderr goes to a log file. By default, output (stdout and stderr) goes to the screen. You can redirect it to files with operators like >, >>, 2>, and 2>>.

31.3.2 Question 2

What is the difference between the > and >> operators?

The first prints to the screen, while the second appends to a file. The first redirects standard out to a file, while the second redirects standard error to a file. The first pipes redirects standard out to a file, while the second pipes standard out into another command. The first redirects standard out and overwrites an existing file, while the second redirects and appends it to the file.

31.3.3 Question 3

How could you print lines 50-60 of a file? There are two correct answers.

31.3.4 Question 4

For an ordinary bash script (not a script you need to submit as a Slurm job), what lines should you always include?

#!/bin/bash and set -euxo pipefail #SLURM bash sbatch

31.3.5 Question 5

For a slurm script, what additional lines do you need to add at the top of a bash script, after the line with #!/bin/bash?