Sponsored Content
Top Forums Shell Programming and Scripting How to read the output of a command line by line and pass it as a variable? Post 303004112 by bakunin on Tuesday 26th of September 2017 05:06:10 PM
Old 09-26-2017
""

Quote:
Originally Posted by Samah
I tried using while loop with no luck and unsure what exactly is missing in my code.
I would perhaps be able to tell you that, provided i could see it. As it is my crystal ball is currently in repair and i cannot see the code on your computer from here.

I can still tell you how to write a while-loop, though, because it should provide exactly what you want:

Code:
....
InFile="/path/to/your/inputfile"
line=""

while read line ; do
     echo "the line read: $line"
done < "$InFile"

This will read the content of the (text-)file "/path/to/your/inputfile" and output it line by line with a prefixed text of "the line read: ". The content of the line in question is in the variable "line" which you can use to base your own code on.

Notice that this will fail if the file is DOS-style formatted (that is, has CR/LF-line separators instead of the UNIX-style newline characters).

If the file contains things you want to filter out before processing it (like i.e. shell-style comments) you can use a filter to pipe into the while-loop like this (replace "<b>" and "<t>" with literal blank/tab characters, the sed-command removes leading/trailing whitespace, comments and empty lines):
Code:
....
InFile="/path/to/your/inputfile"
line=""

sed 's/#.*//;s/^[<b><t>]*//;s[<b><t>]*$//;/^$/d' "$InFile" |\
while read line ; do
     echo "the line read: $line"
done

I hope this helps.

bakunin
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

read a file as input and pass each line to another script

Hi, I am trying to write a ftp script which will read a file for filenames and ftp those files to another server. Here's my ftp script, but it's scanning the current directory for file names. My question is how can I pass multiple files (these files will have the name of data files that need to... (0 Replies)
Discussion started by: sajjad02
0 Replies

2. UNIX for Dummies Questions & Answers

Assigning the output of a command to a variable, where there may be >1 line returned?

Hello I am using unix CLI commands for the Synergy CM software. The command basically searches for a folder ID and returns the names of the projects the folder sits in. The result is assigned to a variable: FIND_USE=`ccm folder -fu -u -f "%name"-"%version" ${FOLDER_ID}` When the command... (6 Replies)
Discussion started by: Glyn_Mo
6 Replies

3. Shell Programming and Scripting

Pass command line argument to variable

Hi, I had written a shell script to pass command line argument to variable in a function. Here is my code: main if ; then .$1 echo $1 get_input_file else echo "input file $1 is not available" fi get_input_file() { FILE = "$1" echo $FILE } (10 Replies)
Discussion started by: Poonamol
10 Replies

4. Shell Programming and Scripting

Blank as variable/output when run from command line

When I run this: PDHDURL=`/usr/bin/curl --silent http://www.phdcomics.com/comics.php | /usr/bin/grep -o http://www.phdcomics.com/comics/archive/.*.gif | head -1` echo -e "$PHDURL" It is totally blank. However, when I just run it from the terminal: /usr/bin/curl --silent... (2 Replies)
Discussion started by: killer54291
2 Replies

5. Shell Programming and Scripting

How to read a file line by line and store it in a variable to execute a program ?

Hello, I am quite new in shell scripting and I would like to write a little scritp to run a program on some parameters files. all my parameters files are in the same directory, so pick them up with ls *.para >>dirafter that I have a dir file like that: param1.para param2.para etc... I... (2 Replies)
Discussion started by: shadok
2 Replies

6. Shell Programming and Scripting

read line and run a different command according to the output

Hi. I'm trying to write a script that reads a line on a file and runs a different command for a different line output. For example, if it finds the word "Kuku" on the line it sends mail to Kuku@kuku.com. Otherwise, it sends mail to Lulu@lulu.com. TIA. (2 Replies)
Discussion started by: Doojek9
2 Replies

7. Shell Programming and Scripting

Passing the value of variable which is read from command line in called script

Hi, I am calling a Perl script in my shell script. When Perl script is executed it asks for a answer to be entered by user from terminal. How can i pass that value from my shell script ?? I know I can change perl script to default the answer but i dont have access to do that so only option i... (5 Replies)
Discussion started by: varun22486
5 Replies

8. Shell Programming and Scripting

How to read a two files, line by line in UNIX script and how to assign shell variable to awk ..?

Input are file and file1 file contains store.bal product.bal category.bal admin.bal file1 contains flip.store.bal ::FFFF:BADC:CD28,::FFFF:558E:11C5,6,8,2,1,::FFFF:81C8:CA8B,::FFFF:BADC:CD28,1,0,0,0,::FFFF:81C8:11C5,2,1,0,0,::FFFF:81DC:3111,1,0,1,0 store.bal.... (2 Replies)
Discussion started by: veeruasu
2 Replies

9. Shell Programming and Scripting

Ksh: Read line parse characters into variable and remove the line if the date is older than 50 days

I have a test file with the following format, It contains the username_date when the user was locked from the database. $ cat lockedusers.txt TEST1_21062016 TEST2_02122015 TEST3_01032016 TEST4_01042016 I'm writing a ksh script and faced with this difficult scenario for my... (11 Replies)
Discussion started by: humble_learner
11 Replies

10. UNIX for Beginners Questions & Answers

Get an output of lines in pattern 1st line then 10th line then 11th line then 20th line and so on.

Input file: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 (6 Replies)
Discussion started by: Sagar Singh
6 Replies
fmt(1)								   User Commands							    fmt(1)

NAME
fmt - simple text formatters SYNOPSIS
fmt [-cs] [-w width | -width] [inputfile...] DESCRIPTION
fmt is a simple text formatter that fills and joins lines to produce output lines of (up to) the number of characters specified in the -w width option. The default width is 72. fmt concatenates the inputfiles listed as arguments. If none are given, fmt formats text from the standard input. Blank lines are preserved in the output, as is the spacing between words. fmt does not fill nor split lines beginning with a `.' (dot), for compatibility with nroff(1). Nor does it fill or split a set of contiguous non-blank lines which is determined to be a mail header, the first line of which must begin with "From". Indentation is preserved in the output, and input lines with differing indentation are not joined (unless -c is used). fmt can also be used as an in-line text filter for vi(1). The vi command: !}fmt reformats the text between the cursor location and the end of the paragraph. OPTIONS
-c Crown margin mode. Preserve the indentation of the first two lines within a paragraph, and align the left margin of each subsequent line with that of the second line. This is useful for tagged paragraphs. -s Split lines only. Do not join short lines to form longer ones. This prevents sample lines of code, and other such formatted text, from being unduly combined. -w width | -width Fill output lines to up to width columns. OPERANDS
inputfile Input file. ENVIRONMENT VARIABLES
See environ(5) for a description of the LC_CTYPE environment variable that affects the execution of fmt. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWcsu | +-----------------------------+-----------------------------+ SEE ALSO
nroff(1), vi(1), attributes(5), environ(5) NOTES
The -width option is acceptable for BSD compatibility, but it may go away in future releases. SunOS 5.10 9 May 1997 fmt(1)
All times are GMT -4. The time now is 10:53 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy