10 lệnh Linux hiệu quả ít được biết đến – Phần IV
Lệnh strace
Lệnh strace là một công cụ gỡ lỗi được sử dụng chủ yếu cho mục đích sửa lỗi trong Linux. Nó có thể không được cài đặt mặc định trong hệ thống của bạn và bạn có thể cần apt hoặc yum để cài đặt gói cần thiết.
Theo dõi việc thực thi một lệnh bằng lệnh strace: Lệnh strace chấp nhận nhiều đối số và có nhiều tùy chọn. Tham khảo trang man để biết thông tin chi tiết.
root@tecmint [~]# strace pwd
Đầu ra mẫu:
execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "7ELF execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360\355\1I;\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 .... execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360\355\1I;\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 .... execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360\355\1I;\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 .... execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360\355\1I;\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 .... execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360\355\1I;\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 .... execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360\355\1I;\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 .... execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360\355\1I;\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 .... execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360\355\1I;\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 .... execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360\355\1I;\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 .... > execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360\355\1I;\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 .... execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360\355\1I;\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 .... execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360\355\1I;\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 .... execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360\355\1I;\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 .... 05I; execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360\355\1I;\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 .... execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360\355\1I;\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 .... execve("/bin/pwd", ["pwd"], [/* 29 vars */]) = 0 brk(0) = 0x728000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0df2000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=38427, ...}) = 0 mmap(NULL, 38427, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f29b0de8000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360\355\1I;\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 .... "..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1922152, ...}) = 0 mmap(0x3b49000000, 3745960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b49000000 mprotect(0x3b4918a000, 2093056, PROT_NONE) = 0 mmap(0x3b49389000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189000) = 0x3b49389000 mmap(0x3b4938e000, 18600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b4938e000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de7000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f29b0de5000 ....
Lệnh disown -a && exit
Hầu hết các quản trị viên hệ thống sử dụng lệnh screen để kiểm soát các công việc đang chạy trong nền terminal. Giả sử bạn có một công việc chạy lâu và muốn tách rời khỏi terminal, bạn sử dụng lệnh screen để làm điều đó. Nhưng nếu bạn không biết cách sử dụng screen, thì lệnh disown sẽ giúp bạn.
Lệnh disown được sử dụng để chạy các công việc liên tục trong nền ngay cả sau khi bạn đóng phiên terminal. Cú pháp của lệnh disown là:
root@tecmint [~]# Command; disown -a && exit
Để tách rời lại công việc đang chạy lâu trong terminal, sử dụng lệnh jobs để tìm số công việc và sau đó sử dụng disown %n, trong đó n là số công việc. Để xác minh công việc thực sự đang chạy, sử dụng lệnh ps hoặc top. Lệnh nohup là một lựa chọn thay thế cho lệnh disown.
Lệnh getconf LONG_BIT
Lệnh trên sẽ hiển thị kiến trúc máy của bạn là 32 bit hay 64 bit?
root@tecmint [~]# getconf LONG_BIT 32
Hiển thị ngày trên Terminal
Lệnh dưới đây là sự kết hợp của một số lệnh, có thể gọi là một đoạn mã. Đối với người làm việc trong shell hoặc terminal, việc xem ngày hệ thống hiện tại là công việc mất công. Bạn phải gõ lệnh "date" để kiểm tra ngày hôm nay.
Chỉ cần thực thi lệnh dưới đây trên dấu nhắc và xem ngày, giờ ở góc phải trên cùng của terminal.
root@tecmint [~]# while sleep 1;do tput sc;tput cup 0 $(($(tput cols)-29));date;tput rc;done &
Lệnh convert
Sự kết hợp lệnh trên thực hiện đi trình cho tôi điều này. Giả sử bạn cần đầu ra của lệnh tree (cho thư mục /etc/x11) dưới dạng hình ảnh. Những gì bạn cần làm trên terminal là:
root@tecmint:/etc/X11# tree | convert label:@- /home/avi/tree.png
Đầu ra của lệnh trên có thể được nhìn thấy tại vị trí đã chỉ định (ở đây là thư mục home) với tên tệp được chỉ định là tree.png.
Lệnh watch -t -n1 "date +%T|figlet"
Lệnh này rất thú vị, chúng ta sẽ chuyển tiếp 'figlet' để hiển thị đồng hồ kỹ thuật số chạy trên terminal. Hãy kiểm tra thử, nhớ rằng bạn phải cài đặt figlet trên hệ thống của mình, hãy sử dụng apt hoặc yum để cài đặt gói cần thiết.
root@tecmint [~]# watch -t -n1 "date +%T|figlet"
Lệnh host và dig
Mặc dù lệnh "host" và "dig" không phải là lệnh ít được biết đến, nhưng vẫn không được sử dụng thường xuyên. Lệnh host là tiện ích tra cứu DNS.
root@tecmint [~]# host www.google.com www.google.com has address 173.194.66.147 www.google.com has address 173.194.66.105 www.google.com has address 173.194.66.99 www.google.com has address 173.194.66.104 www.google.com has address 173.194.66.106 www.google.com has address 173.194.66.103 www.google.com has IPv6 address 2a00:1450:400c:c03::68 root@tecmint [~]# dig www.google.com ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.6 <<>> www.google.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<
Lệnh dstat
Lệnh dstat là một công cụ linh hoạt, tạo ra các thống kê liên quan đến tài nguyên hệ thống. Mặc định, hệ thống của bạn có thể chưa cài đặt 'dstat'. Hãy sử dụng apt hoặc yum để cài đặt 'dstat' trước khi sử dụng công cụ này để tạo ra bảng màu sắc và mô tả tài nguyên hệ thống.
root@tecmint [~]# dstat
Lệnh bind -p
Lệnh 'bind -p' sẽ hiển thị tất cả các phím tắt có sẵn cho shell BASH.
root@tecmint [~]# bind -p
Đầu ra mẫu:
"\C-g": abort "\C-x\C-g": abort "\e\C-g": abort "\C-j": accept-line "\C-m": accept-line # alias-expand-line (not bound) # arrow-key-prefix (not bound) # backward-byte (not bound) "\C-b": backward-char "\eOD": backward-char "\e[D": backward-char "\e!": complete-command "\e/": complete-filename "\e@": complete-hostname "\e{": complete-into-braces "\e~": complete-username "\e$": complete-variable # copy-backward-word (not bound) # copy-forward-word (not bound) # copy-region-as-kill (not bound) .... ....
Lệnh touch /forcefsck
Lệnh trên sẽ tạo ra một thư mục trống 'forcefsck' trong thư mục gốc. Điều này sẽ buộc hệ thống Linux kiểm tra hệ thống tệp trong lần khởi động tiếp theo.
root@tecmint [~]# touch /forcefsck
Mọi người cũng tìm kiếm: etcgldrmau
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