Anand Pandit's Blog

Restart the system , wait till grub appears. Select the kernel you want to boot into and press e to enter into edit mode. Edit the line which starts with kernel , some thing like this           kernel /boot/vmlinuz-X.X.X.X.X. ro root=LABEL=/ rhgb quiet      4. Add keyword 'single' at the end of the line and press enter to exit edit mode.      5. Now select the kernel and press b to boot into single usermode.     

We may some time required to boot in single user mode in linux to fix some issues with the linux. Some times when we boot into single user mode in linux we might see the root volume(/)  as read only and we can edit the config files inside root volume due to this. Solution to this is mounting the root volume (/) in read/write mode using the following command in single user mode. # mount -L / / -t ext3 -o remount,rw

Do you want to find what system calls are being called when you execute a command , then run the strace command as below $strace -c /bin/ls This command will list all the system calls made by "ls" command with cpu time spent on each system calls.