Very nice rowanthorpe.. I try to use bash builtins to spawn as few subshells and processes with fd's as possible.. always on a some server.
The pipe vs. redir question is one I've been trying to figure out too.. One of the best ways I've found to handle that is by using exec manually on fds. Consider this dos2unix clone and it's alternate way of determining input. N6=/dev/null personal pref..
And strangely enough, earlier today I was doing some work on my own builtin MORE command, basically I wanted a cat pager, this does pretty good but I've only had it a day..
Finally, here's the shcat I use.. and if you do $ cat file | shcat | head, you get an error from the pipe issue you talk about. However you can work around it with an $ exec 2>&1 in the correct place.
Also, these 2 aliases I have created over time that work very well for stuff like this.
---------- Post updated at 02:13 AM ---------- Previous update was at 02:08 AM ----------
part of my shell session from earlier today... I was actually trying to make the separator be a null.. might be useful to know there are several ways to output nulls..
STEP 1
# Set variable
FILE=/tmp/mainfile
SEARCHFILE =/tmp/searchfile
# THIS IS THE MAIN FILE.
cat /tmp/mainfile
Interface Ethernet0/0 "outside", is up, line protocol is up
Hardware is i82546GB rev03, BW 100 Mbps
Full-Duplex(Full-duplex), 100 Mbps(100 Mbps)
MAC address... (6 Replies)
Hi ,
I am trying to write an shell, which reads a text file (from a location) having a list of numbers of strictly 5 digits only ex: 33144
Now my script will check :
1) that each entry is only 5 digits & numeric only, no alphabets, & its not empty.
2)then it executes a shell script called... (8 Replies)
Hi All,
I'm trying to figure out which are the trusted-ips and which are not using a script file.. I have a file named 'ip-list.txt' which contains some ip addresses and another file named 'trusted-ip-list.txt' which also contains some ip addresses. I want to read a line from... (4 Replies)
hello all
I'm writing a bash script and I need to read data from a file line by line
The number of words of each line is not known and I want to check if anywhere
in the line exists the substring www..That substring is a string by itself
or a substring of other strings.So what I tried so far... (4 Replies)
Hello,
I need a program that read a file line by line and prints out lines 1, 2 & 3 after an empty line... An example of entries in the file would be:
SRVXPAPI001 ERRO JUN24 07:28:34 1775
REASON= 0000, PROCID= #E506 #1065: TPCIPPR, INDEX= 003F
... (8 Replies)
Hi All,
Am trying to write wrapper shell/bash script on a utility tool for which i need to pass 2 files as arugment to execute utility tool.
Wraper script am trying is to do with above metion 2 files.
utility tool accepts :
a. userinfo file : which contains username
b. item file : which... (2 Replies)
Hi all,
I have a log file say Test.log that gets updated continuously and it has data in pipe separated format. A sample log file would look like:
<date1>|<data1>|<url1>|<result1>
<date2>|<data2>|<url2>|<result2>
<date3>|<data3>|<url3>|<result3>
<date4>|<data4>|<url4>|<result4>
What I... (3 Replies)
Heyas
I'm trying to read/display a file its content and put borders around it (tui-cat / tui-cat -t(ypwriter).
The typewriter-part is a 'bonus' but still has its own flaws, but thats for later.
So in some way, i'm trying to rewrite cat using bash and other commands.
But sadly it fails on... (2 Replies)
Hello,
I'm works on Ubuntu server
My goal : I would like to read file line per line, but i want to started at the end of file.
Currently, I use instructions :
while read line;
do
COMMAND
done < /var/log/apache2/access.log
But, the first line, i don't want this. The file is long... (5 Replies)
I have a file
file_name_O.txt
The file can have different number of other files names or nothing
I will check
cnt=`wc -l file_name_0.txt`
if ;then
exit 1
fi
Now I have to start checking file names, i.e. read txt file line by line. If amount of ,lines equal 1, I can... (4 Replies)