use f-strings in example pipelines

example_pipelines/basic.py

@@ -26,15 +26,15 @@
 tgt = "pipeline_output/test.out"
 
 # build the command
-cmd = "shuf -i 1-500000000 -n 10000000 > " + tgt
+cmd = f"shuf -i 1-500000000 -n 10000000 > {tgt}"
 
 # and run with run().
 pm.run(cmd, target=tgt)
 
 # Now copy the data into a new file.
 # first specify target file and build command:
 tgt = "pipeline_output/copied.out"
-cmd = "cp pipeline_output/test.out " + tgt
+cmd = f"cp pipeline_output/test.out {tgt}"
 pm.run(cmd, target=tgt)
 
 # You can also string multiple commands together, which will execute

example_pipelines/hello_pypiper.py

@@ -12,7 +12,7 @@
 
 # Now build a command-line command however you like, and pass it to pm.run()
 target_file = "hello_pypiper_results/output.txt"
-cmd = "echo 'Hello, Pypiper!' > " + target_file
+cmd = f"echo 'Hello, Pypiper!' > {target_file}"
 pm.run(cmd, target_file)
 
 pm.stop_pipeline()