[jayhemnani9910]

pidof takes argv[0] as the first space-separated word of the joined command line, and only compares that. Two common cases miss:

• Servers that rewrite their title. sshd's listener shows up as sshd: /usr/sbin/sshd -D [listener] 0 of 10-100 startups, which becomes sshd:. So pidof sshd finds nothing and pidof sshd: matches. Any program with a title like name: worker process has the same problem.
• A process started with another argv[0] (exec -a, or a program that sets its own name) isn't found by its program name.

$ ./target/debug/procps pidof sshd; echo $?
1
$ pidof sshd    # procps-ng 4.0.4
2096

Now it matches the way procps-ng's pidof does:

• the base name of the whole argv[0], read from /proc/PID/cmdline without joining the arguments
• the base name of /proc/PID/exe, also when cut to the 15 bytes the kernel keeps for the process name
• the process name, when argv[0] has a space in it (a rewritten title)

The -x script check reads its argument the same way. Nothing else changes.

Testing:

• New test_process_with_another_argv0 copies /bin/sh under its own name and runs it once with the title pidoftitletest: worker process and once with argv[0] another-argv0. pidof pidoftitletest has to find it and pidof pidoftitletest: must not. It fails on main. The spawn retries on ETXTBSY, since other tests fork while the copy can still be open for writing.
• cargo test: 225 passed (224 on main), clippy and rustfmt clean.
• Compared with pidof from procps-ng 4.0.4 (built from the release tarball, since Ubuntu's pidof is sysvinit's) on the same running system: 36 names over test processes (titles with spaces, exec -a, a 19-byte program name, a path with a space, a renamed perl $0, shell scripts with and without -x) and system daemons (sshd, systemd, init, cron, dbus-daemon, polkitd, ...). All match, as do -s, -o, -q and several names at once. The rest were a short-lived subshell in pidof bash and the -d alias, which this pidof adds on purpose.

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[codecov]

Codecov Report

❌ Patch coverage is 51.11111% with 22 lines in your changes missing coverage. Please review.
✅ Project coverage is 19.53%. Comparing base (67832aa) to head (9537be9).
⚠️ Report is 16 commits behind head on main.

Files with missing lines	Patch %	Lines
src/uu/pidof/src/pidof.rs	0.00%	19 Missing ⚠️
tests/by-util/test_pidof.rs	88.46%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #818      +/-   ##
==========================================
+ Coverage   19.20%   19.53%   +0.33%     
==========================================
  Files          68       68              
  Lines       10156    10268     +112     
  Branches      546      556      +10     
==========================================
+ Hits         1950     2006      +56     
- Misses       8206     8262      +56     

Flag	Coverage Δ
macos_latest	6.73% <0.00%> (-0.02%)	⬇️
ubuntu_latest	19.89% <51.11%> (+0.33%)	⬆️
windows_latest	0.02% <0.00%> (-0.01%)	⬇️

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