Question

I’m having serious biggies trying to figure out how to evaluate an expression in a If statement using Tcl. This is what I have:

#!/bin/sh
#The next line executes wish - wherever it is \
exec wish "$0" "$@"

set apid "/var/run/apache2.pid"

set apsta [file exist $apid]

if { $apsta == 1 }

{
    set result ":)"
}

else

{
    set result ":("
}

label .status -text $result
pack .status

and this is what I get from the terminal:

# wan27
Error in startup script: wrong # args: no script following " $apsta == 1 " argument
    while executing
"if { $apsta == 1 }"
    (file "/usr/bin/wan27" line 9)

I’m just trying to output a happy smiley if Apache is running, a sad one if Apache is stopped – based upon the boolean condition whether or not the file “/var/run/apache2.pid” exists …

Answer 1

The syntax of a Tcl if statement is

if condition statement else statement

which must be on one line. Braces allow continuation across lines and their placement is mandatory:

if { $apsta == 1 } {
    set result ":)"
} else {
    set result ":("
}

As you have it written, Tcl sees

if { $apsta == 1 }

and stops there yielding a syntax error.