10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
HI there
I am trying to understand Shell scripting to create my own, I am attempting a few examples can anyone tell me what this means?n=$( expr $n + 1)Tried looking on the internet, but just cannot find its anywhere :( .Help please (4 Replies)
Discussion started by: steve2015
4 Replies
2. Shell Programming and Scripting
Hi
I have bellow script:
t1=`cat node1.txt | grep thread1 | cut -f2 -d '-'`
t2=`cat node2.txt | grep thread2 | cut -f2 -d '-'`
t3=`cat node1_rcat.txt | grep thread1 | cut -f2 -d '-'`
t4=`cat node2_rcat.txt | grep thread2 | cut -f2 -d '-'`
if ]; then
echo "no restore" >> log.log... (6 Replies)
Discussion started by: primo102
6 Replies
3. UNIX for Dummies Questions & Answers
Hi,
I have a text file where i define all the inputs to my shell script:
IP=1.2.3.4
PC=1234
In the shell script, i am trying to read the input variables from the above mentioned text file:
#!/bin/bash
#usage
IP=expr cat /tmp/input.txt | grep IP| cut -d "=" -f2
PC=expr cat... (4 Replies)
Discussion started by: akarnya
4 Replies
4. Shell Programming and Scripting
Hi All,
I'm writing a shell script in KSH, where I want to store the filename, total record count and actual record count of all the source files. The source files reside in 4 different sub-folders under the same root folder.
Below is code:
#!/usr/bin/ksh... (6 Replies)
Discussion started by: jagari
6 Replies
5. UNIX for Dummies Questions & Answers
i have been told that 'let' is faster than 'expr' in terms of performance.
Is this correct? if yes, why is it so?
i am not able to see any performance difference in small arithmetic operations.
Thanks (3 Replies)
Discussion started by: pandeesh
3 Replies
6. UNIX for Dummies Questions & Answers
Hey there
i want to subtract the content from $b from $a. Each variable has got 18 values (normal numbers from 0 - 99).
How can i subtract them? I know i have to use the expr command, this is what i have till now:
a=`cat Tabelle.dat | awk {'print $4'} | awk -F: {'print $1'}`
b=`cat... (1 Reply)
Discussion started by: Mad van Bert
1 Replies
7. Shell Programming and Scripting
$ cat > mtable
#!/bin/sh
#
#Script to test for loop
#
#
if
then
echo "Error - Number missing form command line argument"
echo "Syntax : $0 number"
echo "Use to print multiplication table for given number"
exit 1
fi
n=$1
for i in 1 2 3 4 5 6 7 8 9 10
do
echo "$n * $i = `expr $i \*... (1 Reply)
Discussion started by: jackel7777
1 Replies
8. Red Hat
i am new to shell programming, currently using redhat linux of version
2.4.20-8.
i have problem in executing expr command in the following shell script
$ x=5
$ x='expr $x + 1'
$ echo $x
the output is displaying always
expr $x + 1
Pls guide me for the above query (3 Replies)
Discussion started by: saikumarm80
3 Replies
9. UNIX for Dummies Questions & Answers
Hi friends
how can i execute expr $va1 * $var2
provided i m not supposed to use '/' also the
nglob variable is turned off. (4 Replies)
Discussion started by: ashishj
4 Replies
10. UNIX for Dummies Questions & Answers
Hello!
I want to evaluate some mathematical expressions in a script and I try to use 'expr' command.
Unfortunatally, when I have, for example,
expr 8.2 + 6
the result is 'expr: non-numeric argument'
Why ?
I work on SunOs 5.7.
Thanks in advance
Nathe (5 Replies)
Discussion started by: Nathe
5 Replies
TEST(1) General Commands Manual TEST(1)
NAME
test - set status according to condition
SYNOPSIS
test expr
DESCRIPTION
Test evaluates the expression expr. If the value is true the exit status is null; otherwise the exit status is non-null. If there are no
arguments the exit status is non-null.
The following primitives are used to construct expr.
-r file True if the file exists (is accessible) and is readable.
-w file True if the file exists and is writable.
-x file True if the file exists and has execute permission.
-e file True if the file exists.
-f file True if the file exists and is a plain file.
-d file True if the file exists and is a directory.
-s file True if the file exists and has a size greater than zero.
-t fildes True if the open file whose file descriptor number is fildes (1 by default) is the same file as /dev/cons.
s1 = s2 True if the strings s1 and s2 are identical.
s1 != s2 True if the strings s1 and s2 are not identical.
s1 True if s1 is not the null string. (Deprecated.)
-n s1 True if the length of string s1 is non-zero.
-z s1 True if the length of string s1 is zero.
n1 -eq n2 True if the integers n1 and n2 are arithmetically equal. Any of the comparisons -ne, -gt, -ge, -lt, or -le may be used in place
of -eq. The (nonstandard) construct -l string, meaning the length of string, may be used in place of an integer.
These primaries may be combined with the following operators:
! unary negation operator
-o binary or operator
-a binary and operator; higher precedence than -o
( expr ) parentheses for grouping.
The primitives -b, -u, -g, and -s return false; they are recognized for compatibility with POSIX.
Notice that all the operators and flags are separate arguments to test. Notice also that parentheses and equal signs are meaningful to rc
and must be enclosed in quotes.
EXAMPLES
Test is a dubious way to check for specific character strings: it uses a process to do what an rc(1) match or switch statement can do. The
first example is not only inefficient but wrong, because test understands the purported string "-c" as an option.
if (test $1 '=' "-c") echo OK # wrong!
A better way is
if (~ $1 -c) echo OK
Test whether is in the current directory.
test -f abc -o -d abc
SOURCE
/sys/src/cmd/test.c
SEE ALSO
rc(1)
TEST(1)