Every single command run on a UNIX/Linux/POSIX system will return an exit status. If that exit status is 0, the shell treats that as a boolean true. Any other exit status is treated as a boolean false.
Regards,
Alister
I certainly wouldn't challenge your assertion of that. But I would challenge any assertion that said return codes are always meaningful:
Or perhaps alt's confusion is based on the interpretation of
where the || relates not to the failure of the export command, but more to that of the test which precedes it?
i have this program in bash shell:
#!/bin/bash
array=(20 20 20 20 20)
i=0
j=0
awk '/%/ {print $3}' try.txt|
while (read s)
arr=$s
i=`expr $i + 1`
echo "$i"
end
how can i convert this into c shell? (1 Reply)
Discussion started by: npatwardhan
1 Replies
4. Post Here to Contact Site Administrators and Moderators
Where can I download the VTC - Unix Shell Scripting Advanced complete video.
I don't know in which thread I should post this question.Plz help me out, or just tell me the link in the reply to this post.
Thanks in advance. (0 Replies)
Hi all, i have more questions but its all about variables so lets begin
1st, is possible to list all variables ?
Command env display only shell variables, but what if i declared another variable? Command set display more variables but not defined by me.
2nd, what difference is between set... (24 Replies)
Hello,
I'm working on unix with grep (GNU grep) 2.5.1. I'm going through some of the newer regex syntax using Regular Expression Reference - Advanced Syntax a guide.
ls -aLl /bin | grep "\(x\)"
Which works, just highlights 'x' where ever, when ever.
I'm trying to to get (?:) to work but... (4 Replies)
Hi all
I've got a question regarding error handling in shell scripts. My background is mainly object oriented programming languages, but for a year or so I've been doing more and more (bash) shell scripting (which I quite enjoy by the way).
To handle errors in my scripts I... (3 Replies)
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
1. The problem statement, all variables and given/known data:
I am working on a hands on project. We are creating a script for a corporate phone list. The project I am... (2 Replies)
Hi Folks -
I need help converting a piece of code from batch to bash.
Here is the code:
FOR /f "eol=; tokens=1,2,3,4 delims=, " %%i in (Update_Subvars.txt) do (
ECHO alter database %%i.%%j set variable %%k %%l;
)
What it's doing is retrieving the values from this file:
... (2 Replies)
Hello,
I have a newbe syntax error but I cant find it
syntax error: unexpected end of file
#!/bin/csh
# pe request
#$ -pe mpi_16 32
#### 16 core : 'mpi_16 16' || 24 core : 'mpi_24 24 '
# our Job name
#$ -N test2MD
#$ -S /bin/sh (1 Reply)
Discussion started by: dulceC
1 Replies
LEARN ABOUT HPUX
sh
sh(1) General Commands Manual sh(1)NAME
sh - overview of various system shells
SYNOPSIS
POSIX Shell
option] ... string] [arg ...]
option] ... string] [arg ...]
Korn Shell
option] ... string] [arg ...]
option] ... string] [arg ...]
C Shell
[command_file] [argument_list ...]
Key Shell
DESCRIPTION
Remarks
The POSIX .2 standard requires that, on a POSIX-compliant system, executing the command activates the POSIX shell (located in file on HP-UX
systems), and executing the command produces an on-line manual entry that displays the syntax of the POSIX shell command-line.
However, the command has historically been associated with the conventional Bourne shell, which could confuse some users. To meet stan-
dards requirements and also clarify the relationships of the various shells and where they reside on the system, this entry provides com-
mand-line syntax and a brief description of each shell, and lists the names of the manual entries where each shell is described in greater
detail.
The Bourne shell is removed from the system starting with HP-UX 11i Version 1.5. Please use the POSIX shell as an alternative.
Shell Descriptions
The HP-UX operating system supports the following shells:
POSIX-conforming command programming language and command interpreter
residing in file Can execute commands read from a terminal or a file. This shell conforms to current POSIX standards in
effect at the time the HP-UX system release was introduced, and is similar to the Korn shell in many respects. Similar in
many respects to the Korn shell, the POSIX shell contains a history mechanism, supports job control, and provides various
other useful features.
Korn-shell command programming language and commands interpreter
residing in file Can execute commands read from a terminal or a file. This shell, like the POSIX shell, contains a his-
tory mechanism, supports job control, and provides various other useful features.
A command language interpreter
that incorporates a command history buffer, C-language-like syntax, and job control facilities.
Restricted version of the POSIX shell command interpreter.
Sets up a login name and execution environment whose capabilities are more controlled (restricted) than normal user
shells.
restricted version of the Korn-shell command interpreter
Sets up a login name and execution environment whose capabilities are more controlled (restricted) than normal user
shells.
An extension of the standard Korn Shell
that uses hierarchical softkey menus and context-sensitive help.
+--------------+--------------------+
| To obtain: | Use the command: |
+--------------+--------------------+
| POSIX Shell | /usr/bin/sh ... |
| Korn Shell | /usr/bin/ksh ... |
| C Shell | /usr/bin/csh ... |
| Key Shell | /usr/bin/keysh |
+--------------+--------------------+
These shells can also be the default invocation, depending on the entry in the file. See also chsh(1).
WARNINGS
Many manual entries contain descriptions of shell behavior or describe program or application behavior similar to ``the shell'' with a ref-
erence to ``see sh(1)''.
SEE ALSO
For more information on the various individual shells, see:
keysh(1) Key Shell description.
ksh(1) Korn Shell description.
sh-posix(1) POSIX Shell description.
csh(1) C Shell description.
sh(1)