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Full Discussion: Read the file line by line and do something with lines
Top Forums Shell Programming and Scripting Read the file line by line and do something with lines Post 303019187 by Don Cragun on Sunday 24th of June 2018 05:44:05 PM
Old 06-24-2018
Quote:
Originally Posted by digioleg54
The last loop doesn't support KSH.
Better is the following:


Code:
for file in $(cat file_name.txt)
do
        print "FILE is $file"
done


Thanks for contribution
Hi digioleg54,
I have no idea what you mean by "The last loop doesn't support KSH." Any POSIX shell and any shell based on Bourne shell syntax does support the while loop MadeInGermany suggested:
Code:
while read line
do
  echo "do somthing with $line"
done < file_name_0.txt

And, it is much more efficient and more likely to work than the loop you suggested above. Your has to start up another shell for the command substitution, run the cat utility to get the contents of file_name_0.txt, and will not work correctly if any filename contained in file_name_0.txt contains any IFS characters (by default, including <space> and <tab>). The code MadeInGermany works correctly in this case while your code does not.

While it is true that the code MadeInGermany suggested will not with if you are using csh or one of its derivatives, the code you suggested will not work with those shells either.
 

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LEARN ABOUT MOJAVE

platform::shell

platform::shell(n)					       Tcl Bundled Packages						platform::shell(n)

__________________________________________________________________________________________________________________________________________________

NAME

       platform::shell - System identification support code and utilities

SYNOPSIS

       package require platform::shell ?1.1.4?

       platform::shell::generic shell
       platform::shell::identify shell
       platform::shell::platform shell
_________________________________________________________________

DESCRIPTION

       The platform::shell package provides several utility commands useful for the identification of the architecture of a specific Tcl shell.

       This  package  allows the identification of the architecture of a specific Tcl shell different from the shell running the package. The only
       requirement is that the other shell (identified by its path), is actually executable on the current machine.

       While for most platform this means that the architecture of the interrogated shell is identical to the architecture of  the  running  shell
       this  is  not generally true. A counter example are all platforms which have 32 and 64 bit variants and where a 64bit system is able to run
       32bit code. For these running and interrogated shell may have different 32/64 bit settings and thus different identifiers.

       For applications like a code repository it is important to identify the architecture of the shell which will  actually  run  the  installed
       packages, versus the architecture of the shell running the repository software.

COMMANDS

       platform::shell::identify shell
	      This command does the same identification as platform::identify, for the specified Tcl shell, in contrast to the running shell.

       platform::shell::generic shell
	      This command does the same identification as platform::generic, for the specified Tcl shell, in contrast to the running shell.

       platform::shell::platform shell
	      This command returns the contents of tcl_platform(platform) for the specified Tcl shell.

KEYWORDS

       operating system, cpu architecture, platform, architecture

platform::shell 						       1.1.4							platform::shell(n)
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