Confused ... cd to dir in a ksh script 1

[podsds]

So I have a ksh script that needs to be in a certain dir before executing another script. I tried to code the cd command using a variable and it does not work ... what am I doing wrong? Below is a copy of a simple script put together. Notice that line 9 does not work while and line 14 does work. Also notice that line 15 and 20 do not work, but they previously wored in lines 7 and 11. So I am confused.

Any idesa?

1#!/bin/ksh
2#set -x
3CD=/usr/bin/cd
4ECHO=/usr/bin/echo
5PWD=/usr/bin/pwd
6${ECHO} >> ${log_name}
7${ECHO} "Test 1 Current Directory is `${PWD}`" >>
${log_name}
8${ECHO} >> ${log_name}
9${CD} /export/home
10${ECHO} >> ${log_name}
11${ECHO} "Twst 2 Current Directory is `${PWD}`" >>
{log_name}
12${ECHO} >> ${log_name}
13cd /export/home
14${ECHO} >> ${log_name}
15${ECHO} "Test 3 Current Directory is `${PWD}`" >>
${log_name}
16${ECHO} "Test 3 Part 2 Current Directory is `/usr/bin/pwd`"
>> ${log_name}
17${ECHO} >> ${log_name}
18/usr/bin/cd /export
19${ECHO} >> ${log_name}
20${ECHO} "Test 4 Current Directory is `${PWD}`" >>
${log_name}
21${ECHO} "Test 4 Part 2 Current Directory is `/usr/bin/pwd`"
>> ${log_name}
22${ECHO} >> ${log_name}

Output from script execution, itheratice at terminal

Test 1 Current Directory is /export/home/sysadmin/script/common


Twst 2 Current Directory is /export/home/sysadmin/script/common


./sds[15]: /export/home: cannot execute
Test 3 Current Directory is
Test 3 Part 2 Current Directory is /export/home


./sds[20]: /export/home: cannot execute
Test 4 Current Directory is
Test 4 Part 2 Current Directory is /export/home

 

[vgersh99]

ksh's 'cd' is a builtin command.
using /usr/bin/cd executes the command (/usr/bin/cd) in the subshell NOT changing the effective directory of you current shell.


vlad
+----------------------------+
| #include<disclaimer.h> |
+----------------------------+

 

[podsds]

I can accept this. So just use cd as a builtin no problem.

What do you mape of the PWD in line 15 and 20 ... is it the built in too?

 

[KenCunningham]

PWD is an environment variable which changes depending upon your current location on the box. HTH.

 

[iribach]

all your [{}] are superfluos and confusing,
learn please about the use of [{}] in sh-script.
aaa=aaa
echo ${aaa} # is not wrong NOR necessary
echo ${aaa}.bbb # is not wrong NOR necessary
echo ${aaa}_bbb # is necessary !!!
echo ${aaa}bbb # is necessary !!!

 

[podsds]

Thanks for the lession, but the superflus [{}] don't really bother me, in fact they help me spot variable with in the code.