Sponsored Content
Top Forums Shell Programming and Scripting Having sed to read lines of a file with the use of a variable..Possible? Post 302446788 by hakermania on Thursday 19th of August 2010 05:36:54 PM
Old 08-19-2010
Tools Having sed to read lines of a file with the use of a variable..Possible?

This i will print the second line of a file
sed -n '2p' test2
The use of a variable is impossible here.
Code:
a=1
while [ X"$line" != X"" ]; do
line=`sed -n '$a p' test2`

# do some things here with the line variable
a=`expr $a + 1`
done

But the uotput of sed command is 'p'..... What can i do to use a variable here?Smilie
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

Delete multiple lines containting a variable string using SED.

Good morning, Novice scripter in Unix here, and I've run into and sed task I can't quite wrap my head around. I'm pulling my hair out fast enough as it is and thought I would go to the knowledge bank. I have a sorted file that I'm trying to trim down by deleting any line whose first few... (2 Replies)
Discussion started by: selkirk
2 Replies

2. Shell Programming and Scripting

need sed command to read a path and set to variable

I have a variable called PATH that contains a path example: /Users/rtipton/Desktop/testusers/test I need a sed command to set a variable called USER to the last directory name in that path PATH="/Users/rtipton/Desktop/testusers/test" and from that PATH i need USER to = test I know sed... (4 Replies)
Discussion started by: tret
4 Replies

3. Shell Programming and Scripting

read contents of a file with serveral lines & assign it to a variable

Hi All I have a file for ex .log file which contain several lines within it. I have to read that file contents & assing that to a variable. (2 Replies)
Discussion started by: satyam.sumit
2 Replies

4. Shell Programming and Scripting

read file-print lines in sed

Hello! Im trying to read file contents. Then, print out every line that has "/bens/here" in the file that was read. cat /my/file.now | sed '/bens/here/p' I keep getting the error asking if I need to predeclare sed? What does predeclaring sed mean? Thanks! Ben (2 Replies)
Discussion started by: bigben1220
2 Replies

5. UNIX for Dummies Questions & Answers

sed print certain lines matching variable

I have a very large results file, and a list of filters grep -wf filterlist.txt datafile.txt > outfile.txt The above line works but is very slow and I'm wondering how to make it faster. The items in my filterlist are only relevant to the first column. I don't care if any item in the... (1 Reply)
Discussion started by: sayb
1 Replies

6. Shell Programming and Scripting

replace (sed?) a string in file with multiple lines (string) from variable

Can someone tell me how I can do this? e.g: a=$(echo -e wert trewt ertert ertert ertert erttert erterte rterter tertertert ert) How do i replace the STRING with $a? I try this: sed -i 's/STRING/'"$a"'/g' filename.ext but this don' t work (2 Replies)
Discussion started by: jforce
2 Replies

7. UNIX for Dummies Questions & Answers

When reading a csv file, counter to read 20 lines and wait for minute then read next 20 till end

Hello All, i am a newbie and need some help when reading a csv file in a bourne shell script. I want to read 10 lines, then wait for a minute and then do a reading of another 10 lines and so on in the same way. I want to do this till the end of file. Any inputs are appreciated ... (3 Replies)
Discussion started by: victor.s
3 Replies

8. Red Hat

How to pass value of pwd as variable in SED to replace variable in a script file

Hi all, Hereby wish to have your advise for below: Main concept is I intend to get current directory of my script file. This script file will be copied to /etc/init.d. A string in this copy will be replaced with current directory value. Below is original script file: ... (6 Replies)
Discussion started by: cielle
6 Replies

9. Shell Programming and Scripting

sed read X lines after match

I want to do something like sed -n '/PATTERN/,+10p' and get the ten lines following PATTERN. However, this throws an "expected context address" with the sed that comes with OSX Lion. If that + is a GNUism, can I do this, or do I have to find another tool? (2 Replies)
Discussion started by: jnojr
2 Replies

10. Shell Programming and Scripting

Using sed in a loop/to remove lines contained in variable from file

I've tried numerous commands, but I am not sure how to use sed in a loop. This is what I have: VARZ contains CARD_FILE_LIST and it also contains CARD_FILE_LIST2 so echo "$VARZ" CARD_FILE_LIST CARD_FILE_LIST2 I have a file with 60 lines in /tmp/testfile it and I want those lines deleted... (3 Replies)
Discussion started by: newbie2010
3 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 04:13 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy