RHEL時區(qū)設(shè)置(Time Zone in RHEL)

chinaux

Environment: RHEL 6.1

How to set a correct time zone  in RHEL could  be a headache issue, it was for me a few days ago. For system administrators in China, most of them have no such an issue, since they may do a simple "ln -sf /usr/share/zoneinfo/PRC /etc/localtime" or "cp -a /usr/share/zoneinfo/PRC /etc/localtime", and then a correct timezone is on the output of "date" or "date +%Z". However, what to do if I'd like to see "GMT+8"?

"ln -sf /usr/share/zoneinfo/Etc/GMT+8 /etc/localtime" does give the correct time zone "GMT+8", however, the time is completely wrong, it's the time of US/Pacific. "ln -sf /usr/share/zoneinfo/Etc/GMT-8 /etc/localtime" gives me the right time, however, the time zone "GMT-8" is not what I expect.

"export TZ=GMT-8" in bash gives the correct time, but, the time zone "GMT" is still incorrect.

The right solution is .........

export TZ="<GMT+8>-8"

then, both the time and the time zone are correct!


I've written functions of setting a time zone in system-wide in bash for your reference:

1. backup_file()
   
2. {
   
3. 
   
4. file=$1
   
5. 
   
6. tmpbackup=${file}.tmp
   
7. 
   
8. if [ ! -f $file ]; then
   
9. #       echo "File $file doesn't exist." >&2
   
10. #       return 1
    
11.         touch $tmpbackup
    
12.         restorecon $tmpbackup
    
13.         return 0
    
14. fi
    
15.   
    
16. cp -a $file $tmpbackup
    
17. 
    
18. if [ "X${backup}" == "no" ]; then return 0 ; fi
    
19. 
    
20. if [ ! -f ${file}.${stamp} ]; then
    
21.         cp -a $file ${file}.${stamp}
    
22. fi
    
23. 
    
24. return $?
    
25. }
    
26. 
    
27. # compare a configuration file  against its backup ended with "$stamp"
    
28. compare_files()
    
29. {
    
30. file=$1
    
31. tstamp=$2
    
32. 
    
33. if [ ! -f $file -o ! -f ${file}.${tstamp} ]; then
    
34.         echo "Error: either $file or ${file}.${tstamp} doesn't exist." >&2
    
35.         echo "Error: fail to compare files." >&2
    
36.         return 99
    
37. fi
    
38. 
    
39. if [ "X$(diff $file ${file}.${tstamp})" == "X" ]; then
    
40.         echo "  no changes made to $file."
    
41.         rm -f ${file}.${tstamp}
    
42.         return 0
    
43. else   
    
44.         echo "  $file is now regenerated."
    
45.         return 1
    
46. fi
    
47. 
    
48. }
    
49. 
    
50. set_timezone()
    
51. {
    
52. 
    
53. timezone=$1
    
54. 
    
55. if [ "X${timezone}" == "X" ]; then
    
56.         echo "Error: timezone must be a valid value." >&2
    
57.         return 1
    
58. fi
    
59. 
    
60. echo -e "  new timezone \"${timezone}\" is to be set. "
    
61. echo -e "  current timezone is \"$(date +%Z)\" according to the output of \"# date +%Z\". "
    
62. 
    
63. backup_file /etc/profile
    
64. backup_file /etc/csh.login
    
65.         
    
66. # bash/ksh
    
67. if grep -q "^export[[:space:]]\{1,\}TZ=" /etc/profile; then
    
68.         echo "  current TZ is $(grep '^export[[:space:]]\{1,\}TZ=' /etc/profile  | sed -e 's/.*TZ=//' -e 's/#.*//' -e 's/[[:space:]].*//g') on /etc/profile."
    
69.         grep -v "^export[[:space:]]\{1,\}TZ=" /etc/profile > /etc/profile.tmp
    
70. fi
    
71. 
    
72. # csh
    
73. if grep -q "^setenv[[:space:]]\{1,\}TZ\{1,\}" /etc/csh.login; then
    
74.         echo "  current TZ is $(grep '^setenv[[:space:]]\{1,\}TZ[[:space:]]\{1,\}' /etc/csh.login | sed -e 's/.*TZ[[:space:]]\{1,\}//' -e 's/#.*//' -e 's/[[:space:]].*//g') on /etc/csh.login."
    
75.         grep -v "^setenv[[:space:]]\{1,\}TZ[[:space:]]\{1,\}" /etc/csh.login > /etc/csh.login.tmp
    
76. fi
    
77. 
    
78. echo $timezone | grep -q -E "\+|\-"
    
79. if [ $? -ne 0 ]; then
    
80. 
    
81.    if [ -f /usr/share/zoneinfo/${timezone} ]; then
    
82.         rm -f /etc/localtime
    
83.         cp -a /usr/share/zoneinfo/${timezone} /etc/localtime
    
84.         echo "  timezone is now set to \"$timezone\"."
    
85.    else
    
86.         echo "Error: timezone \"$timezone\" is not supported." >&2   
    
87.    fi
    
88. 
    
89. else
    
90. 
    
91.    if echo $timezone | grep -q '+'; then
    
92.         offsethour=$(echo $timezone | sed -e "s/.*+/\-/")
    
93.    else
    
94.         offsethour=$(echo $timezone | sed -e "s/.*-/\+/")
    
95.    fi
    
96. 
    
97.    sed -e "/^unset i/i\
    
98. export TZ=\"\<${timezone}\>${offsethour}\"
    
99. " /etc/profile.tmp > /etc/profile
    
100. 
     
101.    sed -e "/^set history/i\
     
102. setenv TZ \"\<${timezone}\>${offsethour}\"
     
103. " /etc/csh.login.tmp > /etc/csh.login
     
104. 
     
105. fi
     
106. 
     
107. compare_files /etc/profile $stamp
     
108. compare_files /etc/csh.login $stamp
     
109. 
     
110. rm -f /etc/profile.tmp  /etc/csh.login.tmp
     
111. 
     
112. }

復(fù)制代碼

maochanglu

一般都用 ln -sf /usr/share/zoneinfo/PRC /etc/localtime 吧