Not able to create ctags in linux

Question

I am getting following error after executing "ctags -R".

Command-

pihu@sc[/opt/soe/projects/sr_4k_10_1_x/pihu/sr1] >ctags -R

Output-

/opt/tools/unsupported/bin/ctags: no input files specified.
        Try `/opt/tools/unsupported/bin/ctags --help' for a complete list of options.

Command-

pihu@sc[/opt/soe/projects/sr_4k_10_1_x/pihu/sr1] >which ctags

Output-

/opt/tools/bin/ctags

Additional Information-I used two file .bashrc and .cshrc in /home/pihu path.

.bashrc :-

export PS1="\u@\h\w>"
alias 2k4k='cd /opt/soe/projects/sr_4k_10_1_x/pihu'
alias avm='cd /opt/soe/projects/sr_4k_10_1_x/pihu'
export PATH=$PATH:/opt/tools/unsupported/bin:/opt/tools/bin:/tiara/local/bin:/opt/unsupported/bin:/opt/soe/lb/sr_lbtools/bin:/opt/soe/lb/sr_lbtools:/opt/soe/lb/sr_lbtools/tiara/local/bin:/usr/bin/

Answer 1

For the -R (recurse) option, you still have to supply a path:

ctags -R .

I always prefer to generate the list of files that I want to use first. Something like this:

find . -name *.c -type f > cscope.files
find . -name *.h -type f >> cscope.files

Then I run ctags with the -L option, like this:

ctags -L cscope.files