01-11-2008
shell
Hi,
This one is used to delete certain number of line from the head and end of file in a given direcotory.
Hope it is useful for you.
Quote:
echo "please input how many lines you want cut from the head and end"
read line
echo "input the direcoty"
read dir
cd $dir
for i in *
do
n=`cat $i | wc -l`
m=`expr $n - $line`
rel=`expr $m + 1`
sed -e "1d" -e "$rel,\$d" $i > $i.bak
done
10 More Discussions You Might Find Interesting
1. Programming
Hi, experts,
I would like to create a function that can calculate the total number of lines in a saved text file and delete specific lines in that particular file (I only want the last few lines). Hav anybody have the experience and giv me a hand in this? (9 Replies)
Discussion started by: dniz
9 Replies
2. Shell Programming and Scripting
hello all
I have bunch of files containing lines of text that surrounding by <# .......#> tags
I like to delete this lines from the text files whiteout open the files , can it be done with sed ?
or other unix tool (perl mybe )? (2 Replies)
Discussion started by: umen
2 Replies
3. Shell Programming and Scripting
Hello,
Hello Firends,
I have file like below. I want to remove selected blocks say abc,pqr,lst. how can i remove those blocks from file.
zone abc {
blah
blah
blah }
zone xyz {
blah
blah
blah }
zone pqr {
blah
blah
blah } (4 Replies)
Discussion started by: nrbhole
4 Replies
4. UNIX for Dummies Questions & Answers
Hi everybody!
I need to delete several vertical lines in a huge text file.
It should work like the example below. Delete the vertical lines 2 and 8.
123456789
masldfjla
afsajfwel
sajfljsaf
safsarfrl
sajfeljwq
1345679
msldfja
asajfwl
sjfljsf
sfsarfl
sjfeljq
Is there a... (11 Replies)
Discussion started by: relaxo
11 Replies
5. Shell Programming and Scripting
it will grep for a line and then delete these line. how do i begin to write this script if theres no available one? (3 Replies)
Discussion started by: garfish
3 Replies
6. Shell Programming and Scripting
Hello,
I have a group of text files with many lines in each file.
I need to delete all the lines in each and only leave 2 lines in each file. (3 Replies)
Discussion started by: script_op2a
3 Replies
7. Shell Programming and Scripting
hi guys,
I have very large txt files (200GB) and just want to to delete the first two lines (headers). So far I used
sed -i '1,2d' infile.txtbut this command always takes extremely long as it writes all again. Is there a better way to do it (ie just to delete the lines without writing all... (2 Replies)
Discussion started by: TuAd
2 Replies
8. Shell Programming and Scripting
hey guys,
I tried searching but most 'search and replace' questions are related to one liners.
Say I have a file to be replaced that has the following:
$ cat testing.txt
TESTING
AAA
BBB
CCC
DDD
EEE
FFF
GGG
HHH
ENDTESTING
This is the input file: (3 Replies)
Discussion started by: DeuceLee
3 Replies
9. Shell Programming and Scripting
Hello,
I'm trying to figure out how to use sed or awk to delete single lines in a file. By single, I mean lines that are not touching any other lines (just one line with white space above and below).
Example:
one
two
three
four
five
six
seven
eight
I want it to look like: (6 Replies)
Discussion started by: slimjbe
6 Replies
10. Shell Programming and Scripting
I'm trying to remove a specific number of lines, above and below a specific line of text, highlighted in red:
<STMTTRN>
<TRNTYPE>CREDIT
<DTPOSTED>20151205000001
<TRNAMT>10
<FITID>667800001
<CHECKNUM>667800001
<MEMO>BALANCE
</STMTTRN>
<STMTTRN>
<TRNTYPE>DEBIT
<DTPOSTED>20151207000001... (8 Replies)
Discussion started by: bomsom
8 Replies
EXPR(1) General Commands Manual EXPR(1)
NAME
expr - evaluate arguments as an expression
SYNOPSIS
expr arg ...
DESCRIPTION
The arguments are taken as an expression. After evaluation, the result is written on the standard output. Each token of the expression is
a separate argument.
The operators and keywords are listed below. The list is in order of increasing precedence, with equal precedence operators grouped.
expr | expr
yields the first expr if it is neither null nor `0', otherwise yields the second expr.
expr & expr
yields the first expr if neither expr is null or `0', otherwise yields `0'.
expr relop expr
where relop is one of < <= = != >= >, yields `1' if the indicated comparison is true, `0' if false. The comparison is numeric if
both expr are integers, otherwise lexicographic.
expr + expr
expr - expr
addition or subtraction of the arguments.
expr * expr
expr / expr
expr % expr
multiplication, division, or remainder of the arguments.
expr : expr
The matching operator compares the string first argument with the regular expression second argument; regular expression syntax is
the same as that of ed(1). The (...) pattern symbols can be used to select a portion of the first argument. Otherwise, the
matching operator yields the number of characters matched (`0' on failure).
( expr )
parentheses for grouping.
Examples:
To add 1 to the Shell variable a:
a=`expr $a + 1`
To find the filename part (least significant part) of the pathname stored in variable a, which may or may not contain `/':
expr $a : '.*/(.*)' '|' $a
Note the quoted Shell metacharacters.
SEE ALSO
ed(1), sh(1), test(1)
DIAGNOSTICS
Expr returns the following exit codes:
0 if the expression is neither null nor `0',
1 if the expression is null or `0',
2 for invalid expressions.
EXPR(1)