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When I executed ps ef command in a linux server, I saw that one of the command starts with \_. For example,

\_ /bin/sh /usr/

Could any one please let me know what is the meaning of \_ in this command?

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I think you are confusing the BSD syntax and the standard syntax. Do you mean ps -ef instead of ps ef? Note the dash. – lesmana May 13 '13 at 7:53
@lesmana ps f is the syntax that produces this output (in the default personality). – Gilles May 13 '13 at 22:55
up vote 2 down vote accepted

It means the child process of the parent process ID. Because ps ef will show you list processes in a hierarchy.

This is from man ps:

f     ASCII art process hierarchy (forest)
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