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As sea said, your exit commands are exiting the subshell in which they're located; not the parent shell... But, you can reverse the condition and use multiple && operators with a single || operator....

To add: you can simply replace the subshell construct with code grouping
[[ $($adb_path devices|wc -l) -gt 2 ]] && echo "there's a device connected" || { echo "please connect a device";exit -1;}...

The && and || operators are not a replacement for a proper if - else - fi block".

While one can use subshells, as you did, to do additional tasks if a false has returned, being a subshell, you...

I guess there are non-printing characters in your input file.

Use -v option with cat to show non-printing characters:
cat -v file
For further reference check the man page:
man cat

If you need the functionality of nohup, you could set a trap for SIGHUP to ignore it and ensure required redirections.

Read this (http://perldoc.perl.org/functions/glob.html)

try this...

nohup ./script args > /tmp/out.txt &

You need to do this in two steps: 1) append stdin to file1 2) sort file1 to file2:$ cat >>file1; sort file1 >file2Or try this:$ cat file1 - | tee file1 | sort >file2But the second is highly...

Try: ls -d .*

perl -0pe 's/a\nb/d/g' file

set +o history

@pandeesh
getline x|store the next line in the variable x and skip further display of that line until explictly requested with a print or printf command.
print $0","x|print the current line...

#! /bin/bash

shopt -s extglob

x=$1
while [ ${#x} -gt 0 ]
do
num=${x%%[a-zA-Z]*}; x=${x##+([0-9])}
str=${x%%[0-9]*}; x=${x##+([a-zA-Z])}
for ((i=1; i<=$num; i++))
do
...

Your code takes 0.02s on my machine!! I'm working on a server having 6 quad core cpu's each clocking 2.4 GHz and running on RHEL.

Try this. I don't claim it to be the most efficient. But still...

@max_hammer: I don't think [ "$x" =~ [0-9] ] would work on bash 3.2 either.

I'm using GNU bash, version 3.2.25 and [ "$x" =~ [0-9] ] doesn't work. Regex matching is not supported by single square...

if [ "${ch}" -eq "3" -o "${ch}" -eq "4" ]


Should be


if [ "${ch}" = "3" -o "${ch}" = "4" ]

OR

if [ ${ch} -eq 3 -o ${ch} -eq 4 ]


= for comparing string
-eq for numbers

$ cat input
3a3b4c
4a5d2c
10a12b14c
3abc4xyz5pqr
$
$ perl -ne 'chomp;print$2x$1while(/(\d+)(\D+)/g);print"\n"' input
aaabbbcccc
aaaadddddcc
aaaaaaaaaabbbbbbbbbbbbcccccccccccccc...

Hi.

The purpose is as noted, opens for both input and output:
Opening File Descriptors for Reading and Writing
The redirection operator

[n]<>word

causes the file whose name is the...

Start by checking in /etc/security/limits if there is no tuning to do...

Found this:

Refer to the awk man page:


A pattern-action statement has the form

pattern { action }

A missing { action } means print the line; a missing pattern always...

No, obviously, it will not go away entirely, but that is not what deprecation means. Of course anyone can keep using whatever they like. But is it is good practice on this forum to show solutions...

All files in /var/spool/cron/crontabs are owned by root...
But nothing is stopping you to:

crontab -l >my.cronfile
vi my.cronfile #edit and modify to your needs...
crontab my.cronfile

awk 'BEGIN {print "Header"} END {print "Footer"} 1' file

sed '1s/^/Header\n/; $s/$/\nTrailer/' inputfile

@pandeesh :

Remove the line :

#!/bin/bashfrom your script, and give a try