I need to edit the password file to change the password field to *LK* for a specified account (abctest) like:
abctest:*LK*:135:20::/home/abctest:/sbin/sh
Can anyone help me do this using ed or sed?
Thanks a lot! (6 Replies)
I have a file 'test.out' with contents:
1|1|10|10|I|asdf|
2|1|10|10|I|sdfg|
4|1|10|10|I|hgfj|
34|0|10|10|I|sdg|
I want to modify the fifth column with value 'I' to 'A' for only the last line. Below is what I expect to see:
1|1|10|10|I|asdf|
2|1|10|10|I|sdfg|
... (3 Replies)
Hi all,
I'm writing a script in bash where i'm reading line by line into variable,
and the i want to replace the second filed in the line with another number,
for example if the line looks like this:
10 20 30 40 50
it should look like this:
10 90 30 40 50
and put the new result inside... (1 Reply)
I'm trying to update a text file via sed/awk, after a lot of searching I still can't find a code snippet that I can get to work.
Brief overview:
I have user input a line to a variable, I then find a specific value in this line 10th field in this case. After asking for new input and doing some... (14 Replies)
QUESTION 1:
How do you replace a specific line (i.e. line 4) with a new user defined line (i.e. the contents of SAMS’s name, history, math and English grades have been set already). I have been attempting to use SED (FYI: I don’t have GNU SED) or AWK, but haven’t had any luck. FYI: I am using... (1 Reply)
Hi Guys
I have the following file
Essentially, I am trying to find the right awk/sed syntax in order to produce the following 3 distinct files from the file above:
Basically, I want to print the lines of the file as long as the second field of the current line is equal to the... (9 Replies)
Hi all,
I have a requirement to replace a field with a character as per the length of the field.
Suppose i have a file where second field is of 20 character length. I want to replace second field with 20 stars (*). like ********************
As the field is not a fixed one, i want to do the... (2 Replies)
I am working on a script to convert bank data to a csv file. I have the format done - columns etc. The final piece of the puzzle is to change the second field (after the R) of every line to reflect its' line number in the file. I am stumped. I can use awk on each line but need help looping through... (9 Replies)
Hi,
Need to replace last field in a file(/etc/passwd) ,if first filed matches with particular username.
Scenario:
cat testfor1
deekshi:x:7082:7082::/home/deekshi:/bin/bash
harini1:x:7083:7083::/home/harini1:/bin/bash
Here,if first field contains "deekshi", then i should replace... (4 Replies)
Discussion started by: Sumanthsv
4 Replies
LEARN ABOUT BSD
grep
GREP(1) General Commands Manual GREP(1)NAME
grep, egrep, fgrep - search a file for a pattern
SYNOPSIS
grep [ option ] ... expression [ file ] ...
egrep [ option ] ... [ expression ] [ file ] ...
fgrep [ option ] ... [ strings ] [ file ]
DESCRIPTION
Commands of the grep family search the input files (standard input default) for lines matching a pattern. Normally, each line found is
copied to the standard output. Grep patterns are limited regular expressions in the style of ex(1); it uses a compact nondeterministic
algorithm. Egrep patterns are full regular expressions; it uses a fast deterministic algorithm that sometimes needs exponential space.
Fgrep patterns are fixed strings; it is fast and compact. The following options are recognized.
-v All lines but those matching are printed.
-x (Exact) only lines matched in their entirety are printed (fgrep only).
-c Only a count of matching lines is printed.
-l The names of files with matching lines are listed (once) separated by newlines.
-n Each line is preceded by its relative line number in the file.
-b Each line is preceded by the block number on which it was found. This is sometimes useful in locating disk block numbers by con-
text.
-i The case of letters is ignored in making comparisons -- that is, upper and lower case are considered identical. This applies to
grep and fgrep only.
-s Silent mode. Nothing is printed (except error messages). This is useful for checking the error status.
-w The expression is searched for as a word (as if surrounded by `<' and `>', see ex(1).) (grep only)
-e expression
Same as a simple expression argument, but useful when the expression begins with a -.
-f file
The regular expression (egrep) or string list (fgrep) is taken from the file.
In all cases the file name is shown if there is more than one input file. Care should be taken when using the characters $ * [ ^ | ( ) and
in the expression as they are also meaningful to the Shell. It is safest to enclose the entire expression argument in single quotes ' '.
Fgrep searches for lines that contain one of the (newline-separated) strings.
Egrep accepts extended regular expressions. In the following description `character' excludes newline:
A followed by a single character other than newline matches that character.
The character ^ matches the beginning of a line.
The character $ matches the end of a line.
A . (period) matches any character.
A single character not otherwise endowed with special meaning matches that character.
A string enclosed in brackets [] matches any single character from the string. Ranges of ASCII character codes may be abbreviated
as in `a-z0-9'. A ] may occur only as the first character of the string. A literal - must be placed where it can't be mistaken as
a range indicator.
A regular expression followed by an * (asterisk) matches a sequence of 0 or more matches of the regular expression. A regular
expression followed by a + (plus) matches a sequence of 1 or more matches of the regular expression. A regular expression followed
by a ? (question mark) matches a sequence of 0 or 1 matches of the regular expression.
Two regular expressions concatenated match a match of the first followed by a match of the second.
Two regular expressions separated by | or newline match either a match for the first or a match for the second.
A regular expression enclosed in parentheses matches a match for the regular expression.
The order of precedence of operators at the same parenthesis level is [] then *+? then concatenation then | and newline.
Ideally there should be only one grep, but we don't know a single algorithm that spans a wide enough range of space-time tradeoffs.
SEE ALSO ex(1), sed(1), sh(1)DIAGNOSTICS
Exit status is 0 if any matches are found, 1 if none, 2 for syntax errors or inaccessible files.
BUGS
Lines are limited to 256 characters; longer lines are truncated.
4th Berkeley Distribution April 29, 1985 GREP(1)