#! /bin/ksh
rm -f ./xyz file --- this line is working
// Below any if stmt is not working.
if[-f /var/log/messages ]
then
echo " blah blah "
fi
or I replaced above if with
if[-d ${dirName}/ dirname ]
then
echo "dir exists"
fi
This is also not working.
I am new to KSH. So can someone help why if stmt is not working in KSH.
It's giving me error as
if[-f /var/log/messages ]: not found
syntax error: `then' unexpected
Use space around the square brackets: if [ -f ...
It is also better practice to use:
instead of:
Still it's not working after using space.
Its giving error as
if[ -f /var/log/messages ]: not found #==> I did put one space at start and end of [ ]
syntax error: `then' unexpected
You are still not using enough spaces
if [[ -f /var/log/messages ]]
then
....
fi
Yes I tried to use the space
if[[ -f /var/log/messages ]]
then
echo "This dir not exists."
fi
Error :
if[[ -f /var/log/messages ]]: not found
syntax error: `then' unexpected
---------- Post updated at 09:57 AM ---------- Previous update was at 09:54 AM ----------
After using the 2 spaces still the same error. I dont know why its giving error for IF
if[[ -f /var/log/messages ]]: not found
./rdaMakeWL92.sh[8]: syntax error: `then' unexpected
You need a space either side of [ - between the if and the first [.
ifSPACE[[SPACE ... SPACE]]
OMG ...It really funny now it's working just putting space after IF ... welcome to shell scripting .. 
if [-d /var/log/messages]
then
echo "This dir not exists."
fi
Thanks much for helping me in this.
Surely one space after the "if" and one space after the "[" and one space before the "]".
if [ -f /var/log/messages ]
then
echo "This file exists"
fi
if [ -d /var/log ]
then
echo "This directory exists
fi
if [ ! -d /var/log ]
then
echo "This directory does not exist"
fi
For me - only for ! or negative condition I should have to put space after IF,"[" and "]" but for normal or posivitive condtion only one space after if working. Anyway it good practice to put space as mentioned by you.
It's not a question of "good practice". It's a question of correct syntax.
And to the shell, IF is not the same as if
On the contrary: [ ... ] is standard and portable; [[ ... ]] is not.
[] is necessary for glob-style matching comparison, and he specifically mentioned having ksh...
I find myself at a loss when it comes to testing code. Nobody ever made shells this terrible and old for Linux.
How about dash which is the standard shell (/bin/sh) on Ubuntu ? It is not old but it does not support []
It's nonstandard in many ways, the 'read' command doesn't work right in some situations. Besides, it's not a ksh variant. pdksh seems to be a ksh88 variant, but this guy's shell, whatever it is, might be even older yet..!
It is not necesssary for glob-style matching. A case statement works in all shells.
---------- Post updated at 01:13 PM ---------- Previous update was at 01:09 PM ----------
The dash shell is probably the most POSIX-compliant (i.e., the most standard) shell there is, with the fewest extensions.
In what situations does the read command not work correctly?
The [[ builtin is a kornism and bashism with better-defined semantics than [ (a.k.a. test). If you want your script to be portable as in work with all POSIX-conformant shell script interpreters, you should use the more limited [.
As regards dash and POSIX conformance, according to the current manpage for dash:
Unlike a number of other shells, I do not believe that dash has passed the VSC-PCTS2003 POSIX Certification Test Suite.
It is easy to claim POSIX conformance but a testsuite is the only valid indicator of conformance.
In ksh the bracket type is significant and important. It distinguishes between a "Test" and a "Conditional Expression". There is some common syntax but as soon as you get into boolean expressions they are quite different.
[[ conditional expression ]]
[ test ]
Please tell me what can be done with [[ ... ]] that cannot be done with [ ... ] or case.
ERE matching in modern bash/ksh93:
if [[ "a.3.578.yyy" =~ .\.[0-9]\..*y+ ]]; then
echo hello
fi