The Korn and Bourne Again shells (ksh and bash) have builtin mechanisms for filtering your data from a variable.
The following is taken directly from the book "Learning the Korn Shell" (ISBN 1-56592-054-6):
Keep in mind that this doesn't match regular expressions; the ".*" really matches a "." and then more, not just any character.
It's good for speed, instead of calling basename $path, or saying something like echo $path | sed 's/.*\///g'.
Try using time to figure out how much faster it is to do it that way...
I have a command called
cd $HDRROOT/release/tools/cfg
My query is what it means?
tHat is.... $HDRROOT part is not clear.
If I put this command it says path not found....
I doubt that $HDRROOT is trying to mean smething I am not clear of.
PL help......... (4 Replies)
I found a file in my base folder width the name replace.sh and width the text string.
sed -i "s/$1/$2/g" `grep -ir $1 ./*|grep -v '.svn'|cut -d: -f1`
Wat does it mean and what does it do? (1 Reply)
Can you please tell me what this means?
use grep to find from the file myfile.txt all lines containing the sequence tt but not more 2 ts?
I have no idea. (2 Replies)
Hi,
I have seen in some ksh script, that we are executing shell scripts inside other shell script as
. variable.sh
What is . here? Their is space between . and variabloe. And why we are not executing it like ./variable.sh? I know that . signifies current directory , but what its... (2 Replies)
HI
what does the $(NF) means.
here i want to understand the working.
what i know is that in awk NF argument will tell number of column in a file
i have below file
alpha
a
beta
b
if i use command cat kv | paste - - | awk '{print $1," "$2 "------>"$(NF)}'
i get the o/p as
alpha ... (3 Replies)
Discussion started by: scriptor
3 Replies
LEARN ABOUT X11R4
regcmp
regcmp(1) User Commands regcmp(1)NAME
regcmp - regular expression compile
SYNOPSIS
regcmp [-] filename...
DESCRIPTION
The regcmp command performs a function similar to regcmp and, in most cases, precludes the need for calling regcmp from C programs. Bypass-
ing regcmp saves on both execution time and program size. The command regcmp compiles the regular expressions in filename and places the
output in filename.i.
OPTIONS
- If the - option is used, the output is placed in filename.c. The format of entries in filename is a name (C variable) followed by
one or more blanks followed by one or more regular expressions enclosed in double quotes. The output of regcmp is C source code.
Compiled regular expressions are represented as extern char vectors. filename.i files may thus be #included in C programs, or
filename.c files may be compiled and later loaded. In the C program that uses the regcmp output, regex(abc,line) applies the regu-
lar expression named abc to line. Diagnostics are self-explanatory.
EXAMPLES
Example 1: Examples of the regcmp command.
name "([A-Za-z][A-Za-z0-9_]*)$0"
telno "({0,1}([2-9][01][1-9])$0){0,1} *"
"([2-9][0-9]{2})$1[ -]{0,1}"
"([0-9]{4})$2"
The three arguments to telno shown above must all be entered on one line.
In the C program that uses the regcmp output,
regex(telno, line, area, exch, rest)
applies the regular expression named telno to line.
ENVIRONMENT VARIABLES
A general description of the usage of the LC_* environmental variables can be found in environ(5).
LC_CTYPE Determines how regcmp handles characters. When LC_CTYPE is set to a valid value, regcmp can display and handle text and
filenames containing valid characters for that locale.
LC_MESSAGES Determines how diagnostic and informative messages are presented. This includes the language and style of the messages, and
the correct form of affirmative and negative responses. In the "C" locale, the messages are presented in the default form
found in the program itself (in most cases, U.S. English).
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWtoo |
+-----------------------------+-----------------------------+
|CSI |Enabled |
+-----------------------------+-----------------------------+
SEE ALSO regcmp(3C), attributes(5), environ(5)SunOS 5.10 Dec 20 1996 regcmp(1)