ksh

In kornshell, `basename $0` gives me the name of the current script. How would I exploit $$ or $PPID to implement the singleton pattern of only having one script named `basename $0` executed on this server by any user? ps -ef|grep `basename $0` This will show me all processes which are running that have the name of the currently running script. I need a script which can abort when a thread which is not $$ is running the script named `basename $0`. To provide a race-free mutex, flock is your friend. If you aren't on Linux -- where it's provided by util-linux -- a portable version is available.

I am new to shell, I have a case where I am trying to evaluate a particular column unique values to check if they are valid in a shell script which will be invoked later. From my searches I think cut along with sort & unique is good to do it So my attempt is file=/filepath/*vendor.csv file_categories = `cut -d, -f1 $file |sort |unique` $file should hold file which has vendor in its filename but even after using command substitution (`) the $file is not getting replaced with the correct filename , it just places what is present in file Another example for what I am attempting is a=/stage

It appears that pdksh and mksh has the scoping implementation I expected. For example: readonly x='global' f() { local x readonly x='f' echo $x } g() { local x readonly x='g' echo $x } echo $x f g echo $x pdksh and mksh produce my expected result: global f g global And Bash fails: line 5: local: x: readonly variable Dash and Ksh93 failed my expect, too. (I've changed local to typeset in Ksh93's test.) This seems confusing. UPDATE: I've edited the question. The question before is not stated in a clear way. Bash and Dash don't fail if the global variable is not read only. Korn (ksh93) doesn't

Consider, below code works as expected: if [[ $SOME_VARIABLE = "TRUE" ]]; then echo "Only echoed when \$SOME_VARIABLE stores string \"TRUE\"." fi But when I remove the space surrounding the equality operator it always evaluates to 0 exit status (At least that's what I assume it must be returning as it is taken as true): if [[ $SOME_VARIABLE="TRUE" ]]; then echo "Always true." fi UPDATE: Just to confirm whether the issue lies with the equality operator or not: #!usr/bin/ksh SOME_VARIABLE=FALSE if [[ $SOME_VARIABLE == "TRUE" ]]; then echo "Only echoed when \$SOME_VARIABLE stores string \"TRUE\".

I am writing ksh script to parse a pipe delimited string export dummy="abc" echo "123|456|789" | awk '{split($0,output,"|"); print output[3] output[2] output[1]}' above code seems to work , but I am not able to assign value of output[3] to dummy. Is there a way to do such parsing, but I want to assign the parsing result in a variable within ksh space i.e. dummy (in above sample)? The shell can do it: line="123|456|789" IFS='|' read a b c <<END $line END echo $c # => 789 You can't assign awk variables (i.e. output[3] ) to shell variables (i.e. dummy ), you can only assign the output of awk to a

This is a follow up question to What is the maximum number of characters that the ksh variable accepts? I checked my environment and it's allowing only #include <sys/limits.h> $ cpp << HERE | tail -1 > #include <limits.h> > ARG_MAX > HERE 1048576 Is there a way to increase this? Or any alternatives for while read line; do #parse logic done < $filename To handle really long lines? Based from the records I'm parsing it will not stop at 2M character lines. Environment Details : AIX $ KSH Version M-11/16/88f You could compile a Linux 3.7.x kernel, and edit its include/uapi/linux/limits.h file to

How do I format a date in a KornShell (ksh) script to DD-MON-YYYY? I have tried the following: date '+%d-%h-%Y' It returns 04-Nov-2009 I need for the Nov to be NOV (all caps). Can this be done with the date utility? This is what finally worked on unix(solaris). date '+%d-%h-%Y' | tr [:lower:] [:upper:] returned: 04-NOV-2009 Mark Rushakoff The ^ character forces uppercase in the GNU coreutils date (at least, it does in version 6.9.92.4 of coreutils): $ date '+%d-%^h-%Y' 04-NOV-2009 Unfortunately, ^ is not POSIX standard for date , so you'll probably have to resort to a second command such as

Is there a command in KornShell (ksh) scripting to sort an array of integers? In this specific case, I am interested in simplicity over efficiency. For example if the variable $UNSORTED_ARR contained values "100911, 111228, 090822" and I wanted to store the result in $SORTED_ARR Is it actually an indexed array or a list in a string? Array: UNSORTED_ARR=(100911 111228 090822) SORTED_ARR=($(printf "%s\n" ${UNSORTED_ARR[@]} | sort -n)) String: UNSORTED_ARR="100911, 111228, 090822" SORTED_ARR=$(IFS=, printf "%s\n" ${UNSORTED_ARR[@]} | sort -n | sed ':a;$s/\n/,/g;N;ba') There are several other ways