Trying to learn source rpms

Linux on Servers
1

Hi, Everryone.

I need your expertise, I am trying to learn rpms. I am following an instructional video from pluralsight. Where he download zsh via “yumdownloader --source” in the root directory. As per his instruction I ran the following

  1. rpm -i zsh-5.0.2-34.el7_8.2.src.rpm
  2. went into /root/rpmbuild/SOURCES/ and extracted zsh-5.0.2.tar.bz2 and went into zsh-5.0.2 directory
  3. ran ./configure
  4. ran make
  5. ran make install

All run successfully, as shown in the tutorial video. The question is when he ran zsh anywhere it changed to zshell but in my case I ran zsh in my current directory and it said bash: zsh: command not found.

Can you help me figure what I have overlooked, this system is lab machine so I can provide any logs and configuration file you needed to help me fix this issue I am encountering.
.

2

Did you ‘sudo make install’ or without sudo? Might be in a user’s /bin somewhere.

Search around, see where the binary went on your step 5: ‘sudo find / -type f -iname zsh’

3

I was login as root when I was doing it.

I have ran find / -type f -iname zsh and here is the result:

[root@server1 zsh-5.0.2]# find / -type f -iname zsh
/root/rpmbuild/SOURCES/zsh-5.0.2/Src/zsh
/usr/local/bin/zsh

4

Is that directory in your PATH?

5

Ah, got it. I’m paranoid, so I don’t allow root logins on any of my machines, and forget that others use it.

So, it looks like it built and installed, so it must be either 1) /usr/local/bin is not on your path, or 2) the zsh on the path does not have executable permissions.

For 1, echo $PATH and see if it looks correct. The path is usually built at login time, so log out and back in might fix it. But, #2 might affect #1, if there aren’t any executables in a directory (or it doesn’t exit), then it’s not included in $PATH, so…

For 2, ls -laF /usr/local/bin/zsh and see if it has the ‘x’ bits set for you. This is more or less what I’d expect to see for your executable.

$ ls -laF /usr/bin/zsh
-rwxr-xr-x 1 root root 878288 2020-02-23 20:35 /usr/bin/zsh

My zsh is in /usr/bin (as confirmed by which zsh), since I didn’t build from source…

If you don’t have executable bits set, just chmod 755 /usr/local/bin/zsh, then see if it runs.

1 Like
6

Hi, efahl.

Thank you for your help. I have checked my echo $PATH as a root and this what I got:

[root@server1 tux]# echo $PATH
/sbin:/bin:/usr/sbin:/usr/bin

But ironically when I login as my regular user and show my path it has more:

tux@server1 ~]$ echo $PATH
/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/home/tux/.local/bin:/home/tux/bin

and if run zsh as the regular account it works:

[tux@server1 ~]$ zsh
server1% which zsh
/usr/local/bin/zsh

Because the way I login as root is using “sudo su” so I logged off and login back as root using “su” only and this time it works.

[tux@server1 ~]$ su -
Password:
Last login: Wed Feb 9 06:02:40 ACDT 2022 on pts/1
Last failed login: Wed Feb 9 06:07:21 ACDT 2022 on pts/1
There was 1 failed login attempt since the last successful login.

[root@server1 ~]#
[root@server1 ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin
[root@server1 ~]# zsh
server1# exit

Thank you so much for your help. This helped me a lot in my journey to learn linux

1 Like
7

Yeah, the limited path options in root are a semi-security feature, I think. Makes root less dangerous by limiting the command scope to only those binaries that are part of the base system, not something in /usr/local that a random user plopped in and shadowed the “real” command.

For example, try this:

$ echo 'echo Hello' > /usr/local/bin/cp
$ chmod 755 /usr/local/bin/cp
$ cp .bashrc xxx

Congratulations! You are now a hacker and have put in a trojan copy of the ‘cp’ command. (Don’t forget to rm it.)

1 Like