The "shebang" line is not an ordinary comment (btw do you mean #! /bin/bash)
It instructs the shell that executes the script which interpreter to call on the script when it is the first line of the script.
The value you exit from a script sets $? in the parent shell, this can be used to "report" an error in the running of the script to the parent or to make decisions based on the exit status.
A facile example which checks for the existence of the user in /etc/passwd before running the useradd program.
In the example above the while loop will continue until verified_useradd.sh returns with no error, thus guaranteeing a user has been added (or at least that useradd was called
In a Bourne shell script, I often come across statements involving `sh -c`. I was not able to make out if any reason is there behind that.
example:
echo `sh -c 'date'` killing all server processes
Instead of the above, I can use
echo `date` killing all server processes.
Is there any... (1 Reply)
Hi All,
I am new to shell scripting.
I have a variable which holds a numeric value.I have to check whether this variable holds a value between(0- 8),(8-17)(17-24).How do i write this syntax using if in shell scripting.
Thanks
Vignesh (2 Replies)
I everybody!
I am trying to install the bsh shell on a SCO unix and i don't know how.
The deal is that i have an old SCO unix running with an old system made with cobol, so it works with shell menus and it use a variety of a shell called bsh (Business Shell) so i search for a package to install... (5 Replies)
hi,
I am new script learner,
so my basic doubt is ,
how to store value of any command in a variable example
$ ls | wc -l
i want to stote the output of this in a variable c.
so that i can use c in if else loop.
and when do we use " ` " symbol in script..
can anyone also tell for... (5 Replies)
Hi,
I have a requirement as below which needs to be done viz UNIX shell script
(1) I have to connect to an Oracle database
(2) Exexute "SELECT field_status from table 1" query on one of the tables.
(3) Based on the result that I get from point (2), I have to update another table in the... (6 Replies)
Lets say I wanted to create a script that would show what people are doing on my machine using the w command and refresh in about 6 seconds. What would be the easiest way to do this? I pretty much want the script to loop until I stop it.
I'm using the BASH shell by the way.
Help is appreciated.... (1 Reply)
Im trying to make a script that simply adds a word to the last available line in a txt file without overwriting any previous lines.
Ive googled this and there are great examples but no one explain what each function does, and i dont entirely understand how it works.
Basically Im looking for... (7 Replies)
Hi All,
I have made a file file usercreate.sh & it has to run in tcsh env & needs some path to be set.
my script is as below.
##########################
#!/bin/csh
setenv PATH "/usr/lib/java/class"
setenv LD_LIBRARAY_PATH
###########################
but when i am ruuning my script... (1 Reply)
Hi,
I need to query Oracle database for 100 users. I have these 100 users in a file. I need a shell script which would read this User file (one user at a time) & query database.
For instance:
USER CITY
--------- ----------
A CITY_A
B CITY_B
C ... (2 Replies)
SCRIPT(1) BSD General Commands Manual SCRIPT(1)NAME
script -- make typescript of terminal session
SYNOPSIS
script [-adfpqr] [-c command] [file]
DESCRIPTION
script makes a typescript of everything printed on your terminal. It is useful for students who need a hardcopy record of an interactive
session as proof of an assignment, as the typescript file can be printed out later with lpr(1).
If the argument file is given, script saves all dialogue in file. If no file name is given, the typescript is saved in the file typescript.
Option:
-a Append the output to file or typescript, retaining the prior contents.
-c command
Run the named command instead of the shell. Useful for capturing the output of a program that behaves differently when associated
with a tty.
-d When playing back a session with the -p flag, don't sleep between records when playing back a timestamped session.
-f Flush output after each write. This is useful for watching the script output in real time.
-p Play back a session recorded with the -r flag in real time.
-q Be quiet, and don't output started and ended lines.
-r Record a session with input, output, and timestamping.
The script ends when the forked shell exits (a control-D to exit the Bourne shell (sh(1)), and exit, logout or control-d (if ignoreeof is not
set) for the C-shell, csh(1)).
Certain interactive commands, such as vi(1), create garbage in the typescript file. script works best with commands that do not manipulate
the screen, the results are meant to emulate a hardcopy terminal.
ENVIRONMENT
The following environment variable is used by script:
SHELL If the variable SHELL exists, the shell forked by script will be that shell. If SHELL is not set, the Bourne shell is assumed. (Most
shells set this variable automatically).
SEE ALSO csh(1) (for the history mechanism).
HISTORY
The script command appeared in 3.0BSD.
BUGS
script places everything in the log file, including linefeeds and backspaces. This is not what the naive user expects.
BSD October 17, 2009 BSD