Tagged Questions
3
votes
1answer
123 views
Installing ksh as the standard shell in Redhat: Foolhardy?
I'm not a system administrator, but my organization is considering replacing /bin/sh in Red Hat Enterprise Linux 6+ with a hard link to /bin/ksh. How foolhardy would this be?
The background to this ...
8
votes
7answers
485 views
determine shell in script during runtime
As per my knowledge, to determine the current shell we use echo $0 in the shell. Rather I want my script to check in which shell it is running. So, I tried to print $0 in the script and it returns the ...
0
votes
1answer
69 views
Find all directories, in which user has access to search and echo this directories in shell
I need to find all directories, in which user has access to search(command find) and echo this directories in shell. USER is read from ksh.
for example:
read user
I know, if user want to use find ...
2
votes
2answers
79 views
How do I escape a sub-directory name with an ampersand in it?
Running a kornshell and trying to traverse a directory tree.
Want to cd to a sub-directory named as follows:
-3ab_&_-3dc.img
My question is HOW do I need to escape the ampersand in this name?
...
2
votes
4answers
99 views
Find directories that do not contain subdirectories
I'm writing script is ksh. Need to find all directory names directly under the current directory which contain only files, not subdirectories.
I know that I could use ls -alR and recursively parse ...
1
vote
1answer
60 views
What rules govern the parent-child relationship of processes launched by shell across a pipe?
#!/bin/ksh
# start_service: start the service
my_server_executable 2>&1 | my_pipe_following_shell_script &
exit 0
After I run the above start_service script from command line, it is ...
5
votes
1answer
110 views
Find all users who have more than N processes and echo them in shell
I'm writing a script in ksh. I need to find all users who have more than N processes and echo them in the shell. N is read from ksh.
I know that I should use ps -elf, but how do I parse it, find ...
1
vote
2answers
69 views
case + how to implement equal or less or greater in case syntax
My target is to verify a range of number with (only with case + esac), and print the range. So for example:
If the number is between 0 and 80, print >=0<=80
If the number is between 81 and 100 ...
0
votes
2answers
101 views
Comparison of shells? [closed]
Do shells have any actual advantages or disadvantages? They can all run any binary, they all support pipes and > (output to file). Why would one choose bash over sh, or sh over ksh, etc? Why does ...
3
votes
1answer
180 views
Why does sendmail work differently in different shells?
The following code works when I directly run it in bash shell:
SUBJECT="SUBJECT-"`date`;
MAIL_FROM="abc@site.com";
MAIL_TO="abc@site.com";
MAIL_CC="abc@site.com";
MAIL_FILE="/path/of/html/body.html";
...
1
vote
1answer
42 views
Unsure about the behaviour of my script when writing to log file
I have a very simple ksh script and at certain points I want to write to a log file. I use the following commands in two places...
print "Directory listing 1:\n" > ${LogFile}
ll >> ...
1
vote
1answer
210 views
Korn shell timeout/kill script
I am trying to write a simple Korn shell script to execute a loading process. The process occasionally runs into connectivity issues, so I need to kill it if it runs too long.
I have been trying the ...
3
votes
2answers
273 views
Skip first 3 byte of a file
I am using AIX 6.1 ksh shell
I want to use one liner to do something like this
cat A_FILE | skip-first-3-bytes-of-the-file
I want to skip the first 3 bytes of the first line, is there a way to ...
3
votes
3answers
262 views
What does exit do in an if block in a shell script?
I have a question regarding unix shell script.
Say if you do exit 1 in inner if: will it exit or will it still execute the outer if? The following is a dummy example.
if [ "$PASSWORD" == ...
0
votes
2answers
506 views
print command not found
From the korn shell, I keep getting print command not found. When I run print from the shell, it says the same thing. How would I go about fixing this? printf works fine, but for some reason print is ...
1
vote
1answer
368 views
Do shells support recursion?
I'm trying to write recursive functions in my shell scripts.
Consider the following code:
function printA {
if [[ "$1" = 0 ]]; then
return
else
echo "a$(printA $(("$1" - 1)))"
...
2
votes
1answer
218 views
Time validation with regex
I'd like to make validation about time stamp of one of my log file. But it seems I have problem on my expression in case statement.
TIME value might be something like 11:49 or 2011. And I just want ...
5
votes
1answer
735 views
Korn Shell: End, pgup, pgdown, and delete key not working
So basically my End, Pageup/Pagedown, and Delete key are not working in ksh93. I'm running FreeBSD by the way.
My arrow keys are working, and so is my home key.
Those keys work when I put this in my ...
6
votes
1answer
165 views
Ksh features incorporated into Zsh?
I have been a user of Bash for some time. I want to learn at least one other shell now, so I have been picking up the Korn Shell. However, it doesn't look like Ksh has had major updates for almost ...
5
votes
5answers
336 views
What is the difference between $* and $@?
Consider the following code:
foo () {
echo $*
}
bar () {
echo $@
}
foo 1 2 3 4
bar 1 2 3 4
It outputs:
1 2 3 4
1 2 3 4
I am using Ksh88, but I am interested in other common ...
4
votes
1answer
790 views
What is the most correct way to pass an array to a function?
Consider I have a very large array $large_list, is there a way to write a function that will take the array as an argument? For example:
echo_idx_array () {
arr="$1"
idx="$2"
echo ...
3
votes
4answers
513 views
Formatting the output: Underlining
I wrote the following function in ksh that prints its first argument to the screen and underlines it with the appropriate ammount of - character:
print_underlined () {
word=$1
echo $word
...
2
votes
2answers
251 views
pure shell complex substitution in variable
However it may be impossible, I hope I'm just bad man reader =)
Is there any way to substitute text in variables on several patterns at time or even using back reference?
For example, I have ...
2
votes
0answers
202 views
KSH styling text based menu using STDERR
Is it possible to format the STDERR in order to have a better looking menu using the select command?
I have a simple select
select oChoice in $(<tempMenu.menu) ; do
case "$oChoice" in
...
3
votes
2answers
199 views
issues with GNU tail -f and combination of commands
$ tail -f /logs/filename.log | awk '!(/list)'
I am able to run this command in GNU Linux flavour
But when I written in a script it is not working.
test.ksh:
variable="/logs/filename.log | awk ...
4
votes
3answers
1k views
How to get subshell's PID in Korn Shell (equivalent of $BASHPID)
In bash you have this handy variable: $BASHPID wich always returns the currently running subshell's PID. How can I get a subshell's PID in ksh? For example see the code below:
#!/usr/bin/ksh93
echo ...
3
votes
2answers
666 views
Creating a variable with sed in ksh
I'm using Ksh88 on a Solaris 10 machine.
If I do the following:
foo="one two three"
for i in $foo; do
echo $i;
done
The script executes as expected:
$ ./script.ksh
one
two
three
However if ...
1
vote
2answers
206 views
$2 (field reference) in awk BEGIN is not working
In the following snippet, $2 in awk is returning empty. What am I doing wrong? I am trying to find the difference between MAX and MIN.
#!/bin/ksh
if [ $# -ne 1 ]; then
echo "Usage: sh ...
3
votes
3answers
1k views
How do I run a script n times at same time and how do I simulate a semaphore?
I have a text file, inside of this file is a number, and I have a script.sh in ksh.
The script reads the file and gets the number, then increases the number by 1 and overwrites the new number in the ...
6
votes
5answers
854 views
How to avoid a useless use of cat when parsing a file?
I have a file containing a list of directories. For instance
/foo/bar/dir1
/foo/bar/dir2
/foo/bar/dir3
I want to create all these directories. Here's what I did:
for dir in $(cat myfile); do ...
4
votes
2answers
2k views
How to get a clean environment in a ksh shell?
I need to get rid of all the environment variables in a Ksh shell. I can fork a new instance, but it will inevitably source some init files (as far as I know .profile, .kshrc). Is there a way to ...
3
votes
3answers
813 views
What are the significant differences between different shells? [duplicate]
Possible Duplicate:
What are the fundamental differences between the mainstream *NIX shells?
If I write a shell script in bash, will it run in ksh as well?
if not, what are the ...
5
votes
5answers
348 views
Shell programming, avoiding tempfiles
I often write KSH shell scripts that follow the same pattern:
(1) retrieve output from one or more command
(2) format it using grep|cut|awk|sed and print it to the screen or to a file
In order to ...
2
votes
3answers
353 views
regexp in ksh for extensions tgz, tar.tgz
I'm trying to get a regexp (in ksh) to identify files with only the following extensions: tgz, tar.gz, TGZ and TAR.GZ. I tried several but can't get them to work. I'm using this regexp to select only ...
5
votes
2answers
1k views
Shell script execution on multiple servers
Is it possible to run one part of the ksh/sh script on one server then ssh to another server and continue with the rest of the script? or is there a way around? Anyone had experience with this ?
here ...
22
votes
5answers
1k views
When do you use brace expansion?
I understand what brace expansion is, but I don't know how best to use it.
When do you use it?
Please teach me some convenient and remarkable examples if you have your own tip.
