Se tudo o que você quer saber é o local do comando
Se você quiser saber em qual diretório o comando de nível superior está armazenado, você tem várias opções:
$ which uname
/bin/uname
$ type -a uname
uname is /bin/uname
$ locate uname
/bin/uname
(... SNIP dozens of Windows files on C & D ...)
/usr/lib/klibc/bin/uname
/usr/lib/plainbox-provider-resource-generic/bin/uname_resource
/usr/share/man/man1/uname.1.gz
/usr/share/man/man2/oldolduname.2.gz
/usr/share/man/man2/olduname.2.gz
/usr/share/man/man2/uname.2.gz
A última opção locate retorna todos os arquivos contendo uname não apenas o programa executado a partir do prompt de comando.
strace - rastreia chamadas do sistema e interrompe
Você não precisa dos pid de comandos chamados para encontrar os nomes dos vários comandos que são chamados por uma função. Com strace , todos os nomes dos comandos são exibidos diretamente.
Para o seu exemplo uname -n , a saída é:
$ strace uname -n
execve("/bin/uname", ["uname", "-n"], [/* 62 vars */]) = 0
brk(NULL) = 0x2356000
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=109073, ...}) = 0
mmap(NULL, 109073, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7ff2f9a9f000
close(3) = 0
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "7ELFSTRACE(1) General Commands Manual STRACE(1)
NAME
strace - trace system calls and signals
SYNOPSIS
strace [-CdffhikqrtttTvVxxy] [-In] [-bexecve] [-eexpr]... [-acolumn] [-ofile] [-sstr‐
size] [-Ppath]... -ppid... / [-D] [-Evar[=val]]... [-uusername] command [args]
strace -c[df] [-In] [-bexecve] [-eexpr]... [-Ooverhead] [-Ssortby] -ppid... / [-D]
[-Evar[=val]]... [-uusername] command [args]
DESCRIPTION
In the simplest case strace runs the specified command until it exits. It intercepts
and records the system calls which are called by a process and the signals which are
received by a process. The name of each system call, its arguments and its return value
are printed on standard error or to the file specified with the -o option.
strace is a useful diagnostic, instructional, and debugging tool. System administra‐
tors, diagnosticians and trouble-shooters will find it invaluable for solving problems
with programs for which the source is not readily available since they do not need to be
recompiled in order to trace them. Students, hackers and the overly-curious will find
that a great deal can be learned about a system and its system calls by tracing even
ordinary programs. And programmers will find that since system calls and signals are
events that happen at the user/kernel interface, a close examination of this boundary is
very useful for bug isolation, sanity checking and attempting to capture race condi‐
tions.
$ which uname
/bin/uname
$ type -a uname
uname is /bin/uname
$ locate uname
/bin/uname
(... SNIP dozens of Windows files on C & D ...)
/usr/lib/klibc/bin/uname
/usr/lib/plainbox-provider-resource-generic/bin/uname_resource
/usr/share/man/man1/uname.1.gz
/usr/share/man/man2/oldolduname.2.gz
/usr/share/man/man2/olduname.2.gz
/usr/share/man/man2/uname.2.gz
$ strace uname -n
execve("/bin/uname", ["uname", "-n"], [/* 62 vars */]) = 0
brk(NULL) = 0x2356000
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=109073, ...}) = 0
mmap(NULL, 109073, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7ff2f9a9f000
close(3) = 0
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "7ELFSTRACE(1) General Commands Manual STRACE(1)
NAME
strace - trace system calls and signals
SYNOPSIS
strace [-CdffhikqrtttTvVxxy] [-In] [-bexecve] [-eexpr]... [-acolumn] [-ofile] [-sstr‐
size] [-Ppath]... -ppid... / [-D] [-Evar[=val]]... [-uusername] command [args]
strace -c[df] [-In] [-bexecve] [-eexpr]... [-Ooverhead] [-Ssortby] -ppid... / [-D]
[-Evar[=val]]... [-uusername] command [args]
DESCRIPTION
In the simplest case strace runs the specified command until it exits. It intercepts
and records the system calls which are called by a process and the signals which are
received by a process. The name of each system call, its arguments and its return value
are printed on standard error or to the file specified with the -o option.
strace is a useful diagnostic, instructional, and debugging tool. System administra‐
tors, diagnosticians and trouble-shooters will find it invaluable for solving problems
with programs for which the source is not readily available since they do not need to be
recompiled in order to trace them. Students, hackers and the overly-curious will find
that a great deal can be learned about a system and its system calls by tracing even
ordinary programs. And programmers will find that since system calls and signals are
events that happen at the user/kernel interface, a close examination of this boundary is
very useful for bug isolation, sanity checking and attempting to capture race condi‐
tions.
%pre%%pre%%pre%%pre%%pre%%pre%%pre%%pre%>%pre%%pre%%pre%%pre%P\t%pre%%pre%%pre%%pre%%pre%"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff2f9a9e000
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7ff2f94cb000
mprotect(0x7ff2f968b000, 2097152, PROT_NONE) = 0
mmap(0x7ff2f988b000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1c0000) = 0x7ff2f988b000
mmap(0x7ff2f9891000, 14752, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7ff2f9891000
close(3) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff2f9a9d000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff2f9a9c000
arch_prctl(ARCH_SET_FS, 0x7ff2f9a9d700) = 0
mprotect(0x7ff2f988b000, 16384, PROT_READ) = 0
mprotect(0x606000, 4096, PROT_READ) = 0
mprotect(0x7ff2f9aba000, 4096, PROT_READ) = 0
munmap(0x7ff2f9a9f000, 109073) = 0
brk(NULL) = 0x2356000
brk(0x2377000) = 0x2377000
open("/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=10219008, ...}) = 0
mmap(NULL, 10219008, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7ff2f8b0c000
close(3) = 0
uname({sysname="Linux", nodename="alien", ...}) = 0
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 2), ...}) = 0
write(1, "alien\n", 6alien
) = 6
close(1) = 0
close(2) = 0
exit_group(0) = ?
+++ exited with 0 +++
%pre%%pre%%pre%%pre%%pre%%pre%>%pre%%pre%%pre%%pre%P\t%pre%%pre%%pre%%pre%%pre%"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff2f9a9e000
mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7ff2f94cb000
mprotect(0x7ff2f968b000, 2097152, PROT_NONE) = 0
mmap(0x7ff2f988b000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1c0000) = 0x7ff2f988b000
mmap(0x7ff2f9891000, 14752, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7ff2f9891000
close(3) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff2f9a9d000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff2f9a9c000
arch_prctl(ARCH_SET_FS, 0x7ff2f9a9d700) = 0
mprotect(0x7ff2f988b000, 16384, PROT_READ) = 0
mprotect(0x606000, 4096, PROT_READ) = 0
mprotect(0x7ff2f9aba000, 4096, PROT_READ) = 0
munmap(0x7ff2f9a9f000, 109073) = 0
brk(NULL) = 0x2356000
brk(0x2377000) = 0x2377000
open("/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=10219008, ...}) = 0
mmap(NULL, 10219008, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7ff2f8b0c000
close(3) = 0
uname({sysname="Linux", nodename="alien", ...}) = 0
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 2), ...}) = 0
write(1, "alien\n", 6alien
) = 6
close(1) = 0
close(2) = 0
exit_group(0) = ?
+++ exited with 0 +++
Para mais informações, consulte man strace :
Acima é apenas o começo da manpage para strace