You can edit files from any file system using the EDTF CL command. It is an editor that is similar to the Source Entry Utility (SEU) for editing stream files or database files. Also, you can display a stream file or database file using the DSPF CL command.
Another alternative is to connect to the server using iSeries(TM) Navigator and edit the file using an editor running on the client. The file can be stored in ASCII and still be used by Qshell.
A shell script is just a text file that contains shell commands. It is important to use the right file system for storing shell scripts. Shell scripts are stream data and should be stored in the "root" file system. While it is possible to store shell scripts in source physical files in the QSYS.LIB file system, it causes the shell scripts to use more storage and to run slower.