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Full Discussion: Explanation for Scripts Inner Workings Needed
Top Forums UNIX for Beginners Questions & Answers Explanation for Scripts Inner Workings Needed Post 303033150 by bananasprite on Sunday 31st of March 2019 06:43:21 AM
Old 03-31-2019
Explanation for Scripts Inner Workings Needed
Code:
#!/bin/bash 
n=$l; typeset -a v
x=$(< input.dat)
check(){
if[$l -le 5 -a $l -gt 2]; then
sed 's/Test/Proc/g' file.sh >fl.sh
else
 exit 13
fi
}
check $n
while [$x -ge $n]; do
 x=`expr $x -l`
v[$x]=$x
done
less fi.sh l>/dev/null&& echo yes || exit 1
echo v= ${v[*]}
exit 0

I have file.sh and input.dat in the current filepath.
Can somebody explain what
Code:
x=$(< input.dat)

and
Code:
check $n

and
Code:
less fi.sh l>/dev/null&& echo yes || exit 1

do?
and what the output of
Code:
file.sh 3

would be and why?
Last edited by bananasprite; 03-31-2019 at 08:46 AM..
 

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LEARN ABOUT OSF1

log

log(8)							      System Manager's Manual							    log(8)

NAME

       log - Records input and output from a program

SYNOPSIS

       /usr/sbin/log <logfile> <command>

OPERANDS

       The file in which to record the interaction being logged.  The command to execute.

DESCRIPTION

       The  log  program  runs <command> and logs the input to and output from <command> to the <logfile> file.  Input and output are logged until
       <command> exits, the log program exits, and the exit status of <command> is returned.

       The log program is used by the system  installation  procedure  and  the  it(8)	command  to  create  the  /var/adm/smlogs/install.log  and
       /var/adm/smlogs/it.log installation log files.

RESTRICTIONS

       Because	the  log  program is used in the installation standalone environment, program size was the greatest concern in its implementation.
       The log program does not search for the PATH variable to locate <command> and error messages are terse.

       The log program causes <command> to take standard input from and write standard output and standard error to  UNIX  pipes.   Some  commands
       will  not  be able to operate in this environment; therefore, it is suggested that you use the script(1) command instead.  UNIX shells will
       not issue prompts when run from log unless the shell is started with an explicit interactive switch (-i for most shells).  For example, log
       foo.tmp /sbin/sh -i

       In the previous example, foo.tmp is the name of <logfile>.

       The  log  program  intercepts  end-of-file (usually Ctrl/d).  Therefore programs which normally receive end-of-file as an exit command must
       exit by some other means.

ERRORS

       Log open error

   Explanation:
       The log program was unable to open <logfile>. Verify that the directory exists and that ownerships and permissions are set correctly.

       Exec Error

   Explanation:
       The log program was unable to execute <command>. Verify that you specified a full pathname for <command> and  that  <command>  is  an  exe-
       cutable file.

       Fork Error

   Explanation:
       The log program was unable to create one of the processes it requires to log data.

SEE ALSO

       Commands: it(8), script(1)

																	    log(8)
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