avoid things that look like HTML tags

Author: mr-c

src/introduction/prerequisites.md

@@ -141,8 +141,8 @@ rest of the file.
 The *shebang* is the two-character sequence `#!` at the beginning of a
 script. When the script is executable, the operating system will execute
 the script using the executable specified after the shebang. It is
-considered a good practice to use `/usr/bin/env <executable>` rather than using a hard-coded location, since `/usr/bin/env <executable>`
-looks for the `<executable>` program in the system `PATH`,
+considered a good practice to use `/usr/bin/env [executable]` rather than using a hard-coded location, since `/usr/bin/env [executable]`
+looks for the `[executable]` program in the system `PATH`,
 ```
 
 ## Text Editor

src/introduction/quick-start.md

@@ -51,7 +51,7 @@ of software and libraries used for following the rest of this user guide.
 ## Running "Hello World"
 
 The usage of the `cwltool` command-line executable is basically
-`cwltool [OPTIONS] <CWL_DOCUMENT> [INPUTS_OBJECT]`. You can run the
+`cwltool [OPTIONS] [CWL_DOCUMENT] [INPUTS_OBJECT]`. You can run the
 `hello_world.cwl` workflow without specifying any option:
 
 ```{runcmd} cwltool hello_world.cwl