Editing Symbolic link (section)

===Error handling===
A traditional [[Unix filesystem]] has a tree structure,<ref name="Ritchie">{{cite journal |last1=Ritchie |first1=D.M. |author-link1=Dennis Ritchie |last2=Thompson  |first2=K. |author-link2=Ken Thompson |title=The UNIX Time-Sharing System |journal=Bell System Tech. J. |volume=57 |issue=6 |pages=1905–1929 |date= July 1978 |doi=10.1002/j.1538-7305.1978.tb02136.x |citeseerx=10.1.1.112.595}}</ref> however symbolic links allow it to contain loops.<ref name=":0"/> <!-- ELOOP is the current approach but I used a MicroSoft Xenix which tried to do symlink loop detection at symlink creation time as opposed  to runtime. Naturally you could create two file systems each with a non-looping symlink and then mount them to align those symlinks into a loop and hang program that tried to open them. I don't know the origin of that bug yet. I have found that there is no sign of BSD code in SCCS that has symlinks while lacking ELOOP.  Tested with: "sccsdiff -u -r4.8 -r4.9 SCCS/s.ufs_nami.c"  That leaves either the Xenix bug being written by someone at MS or something MS bought. Come to think of it, maybe BSD wasn't the first UNIX to have symlinks added to it. -->