Yes shell scripts. Just create text files with the content. (You can include an interpreter line if you want.)
That would insure they run as bash shell scripts even if they were called by someone running csh for some reason. Not mandatory but a good practice.
/dev/null a/k/a "the bit bucket" is a place you can send output you don't want. Essentially it just goes away. (Sort of like where Michael Valentine sent people in Stranger in a Strange Land
In the original >/dev/null I'm redirecting output of the command to null because I'm not interested in the output itself - just checking to make sure the command works.
In the 2>/dev/null I'm telling it to send stderr (Standard Error a/k/a File Handle 2) to /dev/null so that only stdout (Standard Output a/k/a File Handle 1) shows up.
The ">" by itself in the original by the way is sending stdout (to /dev/null - the "1" is understood so doesn't have to be listed there though it could be "1>/dev/null" if I wanted.
You can see the difference by doing (assumes you do NOT have a file named ralph):
ls -l * ralph
The above will show all your files (in stdout) AND give an error that "ralph" doesn't exist (in stderr).
If you instead do:
ls -l * ralph >/dev/null
You'll see ONLY the error message that ralph doesn't exist - all of stdout (the files that DO exist) will have been displayed to /dev/null.
If you then do:
ls -l * ralph 2>/dev/null
You'll see the list of files but NOT the error about file ralph not existing because you sent the error to /dev/null.
You can redirect into files if you wish instead of /dev/null. e.g.
ls -l * ralph >ls_stdout.out 2>ls_stderr.out
Would create the files "ls_sdtout.out" and "ls_stderr.out". You'd see all the files that exist in the first file and the error about ralph not existing in the seccond file.
Finally you can do the most common usage which is redirecting BOTH stderr and stdout to a log file:
ls -l * ralph >ls.out 2>&1
The special syntax 2>&1 says to redirect file handle 2 (stderr) into whatever has been defined for file handle 1 (stdout). Since we previously redirect stdout to ls.out it means stderr will also go to ls.out.
In this it is always important to define stdout BEFORE doing the special syntax. If you did:
ls -l * ralph 2>&1 >ls.out
It would send your stderr to stdout but stdout would not have been defined as "ls.out" yet so it would use the default (your terminal session) instead. A lot of people make this mistake so wanted to mention it.