Why running ps -ef is giving error sh: /bin/ps.core: No such file or directory?

Issue

• We are not able to run ps -ef command ,we are getting below error

# ps -ef
sh: /bin/ps.core: No such file or directory
# ldd /bin/ps
        linux-vdso.so.1 =>  (0x00007fff00da9000)
        libstdc++.so.6 => /usr/lib64/libstdc++.so.6 (0x0000003e39800000)
        libm.so.6 => /lib64/libm.so.6 (0x0000003e32000000)
        libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x0000003e37000000)
        libc.so.6 => /lib64/libc.so.6 (0x0000003e31400000)
        /lib64/ld-linux-x86-64.so.2 (0x0000003e31000000)
# bash
#  ps -ef
sh: /bin/ps.core: No such file or directory
#