from :help "A
"Vim fills these registers only when you say so. Specify them as lowercase
letters to replace their previous contents or as uppercase letters to append
to their previous contents"
Is there a way to turn this off?
it's super annoying: when I hold down shift to type double quote " to append to a register, its pretty often the case I hold the shift for a split second too long and input "A instead of "a (so it appends to register a instead of replacing it altogether)
If you wish to implement what #romainl has suggested it can be done in a six lines (three if you don’t mind having magic numbers, leaving unneeded variables and remapping in operator-pending mode):
let s:capshift=char2nr('A')-char2nr('a')
for s:ch in range(char2nr('A'), char2nr('B'))
execute 'nnoremap "'.nr2char(s:ch).' "'.nr2char(s:ch-s:capshift)
execute 'vnoremap "'.nr2char(s:ch).' "'.nr2char(s:ch-s:capshift)
endfor
unlet s:capshift s:ch
. But this solution has a drawback: you now loose ability to wait indefinitely between pressing " and A (unless you want to set notimeout which has problems on its own).
i ended up writing a small patch which adds a "registerappend" option
...with this you can:set noregisterappend to disable it!
diff -r 4cb1f10316ca -r aedf9e836670 src/ops.c
--- a/src/ops.c Thu Oct 11 04:44:33 2012 +0200
+++ b/src/ops.c Tue Oct 16 01:28:47 2012 -0700
## -894,7 +894,8 ## get_yank_register(regname, writing)
else if (ASCII_ISUPPER(i))
{
i = CharOrdUp(i) + 10;
- y_append = TRUE;
+ if(p_regappend)
+ y_append = TRUE;
}
else if (regname == '-')
i = DELETION_REGISTER;
diff -r 4cb1f10316ca -r aedf9e836670 src/option.c
--- a/src/option.c Thu Oct 11 04:44:33 2012 +0200
+++ b/src/option.c Tue Oct 16 01:28:47 2012 -0700
## -2068,6 +2068,9 ## static struct vimoption
(char_u *)NULL, PV_NONE,
#endif
{(char_u *)2000L, (char_u *)0L} SCRIPTID_INIT},
+ {"registerappend", NULL, P_BOOL,
+ (char_u *)&p_regappend, PV_NONE,
+ {(char_u *)TRUE, (char_u *)TRUE} SCRIPTID_INIT},
{"relativenumber", "rnu", P_BOOL|P_VI_DEF|P_RWIN,
(char_u *)VAR_WIN, PV_RNU,
{(char_u *)FALSE, (char_u *)0L} SCRIPTID_INIT},
diff -r 4cb1f10316ca -r aedf9e836670 src/option.h
--- a/src/option.h Thu Oct 11 04:44:33 2012 +0200
+++ b/src/option.h Tue Oct 16 01:28:47 2012 -0700
## -495,6 +495,7 ## EXTERN char_u *p_popt; /* 'printoptions'
EXTERN char_u *p_header; /* 'printheader' */
#endif
EXTERN int p_prompt; /* 'prompt' */
+EXTERN int p_regappend; /* 'registerappend' */
#ifdef FEAT_GUI
EXTERN char_u *p_guifont; /* 'guifont' */
# ifdef FEAT_XFONTSET
Related
#include "calcmarks.h"
// calcmarks, version 1, released Thu Mar 23 13:16:49 WST 2017
int main(int argc, char *argv[])
{
int nmarks = 0;
if(argc == 1) {
nmarks += readmarks(stdin);
Don't care what this code is, what I want is a shellscript to update and version.After do the shellscript,the comment above will become
// calcmarks, version 2, released (time you execute the script)
Tried to do below which didn't work.
a=$(date)
sed -i "_bak" s'/Thu Mar 23 13:16:49 WST 2017/$a/g' "calcmarks.c"
Here is a list of commands that will perform the trick.
Nota : If you are using a different -version-numbering system (2.1, 2.1.1, etc), you'll need to change it slightly.
prev_version=$(sed -n '\%.*// calcmarks, version %!d;s///;s/ .*//p' "$file")
new_version=$((prev_version+1))
curr_date=$(date "+%a %b %d %H:%M:%S %Z %Y")
sed -i -e "s#\(// calcmarks, version \)${prev_version}.*#\1${new_version}, released ${curr_date}#g" "$file"
I have a log directory that consists of bunch of log files, one log file is created once an system event has happened. I want to write an oneline bash script that always monitors the file list and display the content of the newly created file on the terminal. Here is what it looks like:
Currently, all I have is to display the content of the whole directory:
for f in *; do cat $f; done
It lacks the monitoring feature that I wanted. One limitation of my system is that I do not have watch command. I also don't have any package manager to install fancy tools. Raw BSD is all I have. I do have tail, I was thinking of something like tail -F $(ls) but this tails each file instead of the file list.
In summary, I want to modify my script such that I can monitor the content of all newly created files.
First approach - use a hidden file in you dir (in my example it has a name .watch). Then you one-liner might look like:
for f in $(find . -type f -newer .watch); do cat $f; done; touch .watch
Second approach - use inotify-tools: https://unix.stackexchange.com/questions/273556/when-a-particular-file-arrives-then-execute-a-procedure-using-shell-script/273563#273563
You can cram it into a one-liner if you want, but I'd recommend just running the script in the background:
#!/bin/bash
[ ! -d "$1" ] && {
printf "error: argument is not a valid directory to monitory.\n"
exit 1
}
while :; fname="$1/$(inotifywait -q -e modify -e create --format '%f' "$1")"; do
cat "$fname"
done
Which will watch the directory given as the first argument, and cat any new or changed file in that directory. Example:
$ bash watchdir.sh my_logdir &
Which will then cat new or changed files in my_logdir.
Using inotifywait in monitor mode
First this little demo:
Open one terminal and run this:
ext=(php css other)
while :;do
subname=''
((RANDOM%10))||printf -v subname -- "-%04x" $RANDOM
date >/tmp/test$subname.${ext[RANDOM%3]}
sleep 1
done
This will create randomly files named /tmp/test.php, /tmp/test.css and /tmp/test.other, but randomly (approx 1 time / 10), the name will be /tmp/test-XXXX.[css|php|other] where XXXX is an hexadecimal random number.
Open another terminal and run this:
waitPaths=(/{home,tmp})
while read file ;do
if [ "$file" ] &&
( [ -z "${file##*.php}" ] || [ -z "${file##*.css}" ] ) ;then
(($(stat -c %Y-%X $file)))||echo -n new
echo file: $file, content:
cat $file
fi
done < <(
inotifywait -qme close_write --format %w%f ${waitPaths[*]}
)
This may produce something like:
file: /tmp/test.css, content:
Tue Apr 26 18:53:19 CEST 2016
file: /tmp/test.php, content:
Tue Apr 26 18:53:21 CEST 2016
file: /tmp/test.php, content:
Tue Apr 26 18:53:23 CEST 2016
file: /tmp/test.css, content:
Tue Apr 26 18:53:25 CEST 2016
file: /tmp/test.php, content:
Tue Apr 26 18:53:27 CEST 2016
newfile: /tmp/test-420b.php, content:
Tue Apr 26 18:53:28 CEST 2016
file: /tmp/test.php, content:
Tue Apr 26 18:53:29 CEST 2016
file: /tmp/test.php, content:
Tue Apr 26 18:53:30 CEST 2016
file: /tmp/test.php, content:
Tue Apr 26 18:53:31 CEST 2016
Some explanation:
waitPaths=(/{home,tmp}) could be written waitPaths=(/home /tmp) or for only one directory: waitPaths=/var/log
if condition search for filenames matching *.php or *.css
(($(stat -c %Y-%X $file)))||echo -n new will compare creation and modification time.
inotifywait
-q to stay quiet (don't print more then required)
-m for monitor mode: Command don't termine, but print each matching event.
-e close_write react only to specified kind of event.
-f %w%f Output format: path/file
Another way:
There is a more sophisticated sample:
Listenning for two kind of events (CLOSE_WRITE | CREATE)
Using a list of new files flags for knowing which files are new when CLOSE_WRITE event occur.
In second console, hit Ctrl+C, or in new terminal, tris this:
waitPaths=(/{home,tmp})
declare -A newFiles
while read path event file; do
if [ "$file" ] && ( [ -z "${file##*.php}" ] || [ -z "${file##*.css}" ] ); then
if [ "$event" ] && [ -z "${event//*CREATE*}" ]; then
newFiles[$file]=1
else
if [ "${newFiles[$file]}" ]; then
unset newFiles[$file]
echo NewFile: $file, content:
sed 's/^/>+ /' $file
else
echo file: $file, content:
sed 's/^/> /' $path/$file
fi
fi
fi
done < <(inotifywait -qme close_write -e create ${waitPaths[*]})
May produce something like:
file: test.css, content:
> Tue Apr 26 22:16:02 CEST 2016
file: test.php, content:
> Tue Apr 26 22:16:03 CEST 2016
NewFile: test-349b.css, content:
>+ Tue Apr 26 22:16:05 CEST 2016
file: test.css, content:
> Tue Apr 26 22:16:08 CEST 2016
file: test.css, content:
> Tue Apr 26 22:16:10 CEST 2016
file: test.css, content:
> Tue Apr 26 22:16:13 CEST 2016
Watching for new files AND new lines in old files, using bash
There is another solution by using some bashisms like associative arrays:
Sample:
wpath=/var/log
while : ;do
while read -a crtfile ;do
if [ "${crtfile:0:1}" = "-" ] &&
[ "${crtfile[8]##*.}" != "gz" ] &&
[ "${files[${crtfile[8]}]:-0}" -lt ${crtfile[4]} ] ;then
printf "\e[47m## %-14s :- %(%a %d %b %y %T)T ##\e[0m\n" ${crtfile[8]} -1
tail -c +$[1+${files[${crtfile[8]}]:-0}] $wpath/${crtfile[8]}
files[${crtfile[8]}]=${crtfile[4]}
fi
done < <( /bin/ls -l $wpath )
sleep 1
done
This will dump each files (with filename not ending by .gz) in /var/log, and watch for modification or new files, then dump new lines.
Demo:
In a first terminal console, hit:
ext=(php css other)
( while :; do
subname=''
((RANDOM%10)) || printf -v subname -- "-%04x" $RANDOM
name=test$subname.${ext[RANDOM%3]}
printf "%-16s" $name
{
date +"%a %d %b %y %T" | tee /dev/fd/5
fortune /usr/share/games/fortunes/bofh-excuses
} >> /tmp/$name
sleep 1
done ) 5>&1
You need to have fortune installed with BOFH excuses librarie.
If you really not have fortune, you could use this instead:
LANG=C ext=(php css other)
( while :; do
subname=''
((RANDOM%10)) || printf -v subname -- "-%04x" $RANDOM
name=test$subname.${ext[RANDOM%3]}
printf "%-16s" $name
{
date +"%a %d %b %y %T" | tee /dev/fd/5
for ((1; RANDOM%5; 1))
do
printf -v str %$[RANDOM&12]s
str=${str// /blah, }
echo ${str%, }.
done
} >> /tmp/$name
sleep 1
done ) 5>&1
This may output something like:
test.css Thu 28 Apr 16 12:00:02
test.php Thu 28 Apr 16 12:00:03
test.other Thu 28 Apr 16 12:00:04
test.css Thu 28 Apr 16 12:00:05
test.css Thu 28 Apr 16 12:00:06
test.other Thu 28 Apr 16 12:00:07
test.php Thu 28 Apr 16 12:00:08
test.css Thu 28 Apr 16 12:00:09
test.other Thu 28 Apr 16 12:00:10
test.other Thu 28 Apr 16 12:00:11
test.php Thu 28 Apr 16 12:00:12
test.other Thu 28 Apr 16 12:00:13
In a second terminal console, hit:
declare -A files
wpath=/tmp
while :; do
while read -a crtfile; do
if [ "${crtfile:0:1}" = "-" ] && [ "${crtfile[8]:0:4}" = "test" ] &&
( [ "${crtfile[8]##*.}" = "css" ] || [ "${crtfile[8]##*.}" = "php" ] ) &&
[ "${files[${crtfile[8]}]:-0}" -lt ${crtfile[4]} ]; then
printf "\e[47m## %-14s :- %(%a %d %b %y %T)T ##\e[0m\n" ${crtfile[8]} -1
tail -c +$[1+${files[${crtfile[8]}]:-0}] $wpath/${crtfile[8]}
files[${crtfile[8]}]=${crtfile[4]}
fi
done < <(/bin/ls -l $wpath)
sleep 1
done
This will each seconds
for all entries in watched directory
search for files (first caracter is -),
search for filenames begining by test,
search for filenames ending by css or php,
compare already printed sizes with new file size,
if new size greater,
print out new bytes by using tail -c and
store new already printed size
sleep 1 seconds
this may output something like:
## test.css :- Thu 28 Apr 16 12:00:09 ##
Thu 28 Apr 16 12:00:02
BOFH excuse #216:
What office are you in? Oh, that one. Did you know that your building was built over the universities first nuclear research site? And wow, aren't you the lucky one, your office is right over where the core is buried!
Thu 28 Apr 16 12:00:05
BOFH excuse #145:
Flat tire on station wagon with tapes. ("Never underestimate the bandwidth of a station wagon full of tapes hurling down the highway" Andrew S. Tannenbaum)
Thu 28 Apr 16 12:00:06
BOFH excuse #301:
appears to be a Slow/Narrow SCSI-0 Interface problem
## test.php :- Thu 28 Apr 16 12:00:09 ##
Thu 28 Apr 16 12:00:03
BOFH excuse #36:
dynamic software linking table corrupted
Thu 28 Apr 16 12:00:08
BOFH excuse #367:
Webmasters kidnapped by evil cult.
## test.css :- Thu 28 Apr 16 12:00:10 ##
Thu 28 Apr 16 12:00:09
BOFH excuse #25:
Decreasing electron flux
## test.php :- Thu 28 Apr 16 12:00:13 ##
Thu 28 Apr 16 12:00:12
BOFH excuse #3:
electromagnetic radiation from satellite debris
Nota: If some file are modified more than one time between two checks, all modification will be printed on next check.
Although not really nice, the following gives (and repeats) the last 50 lines of the newest file in the current directory:
while true; do tail -n 50 $(ls -Art | tail -n 1); sleep 5; done
You can refresh every minute using a cronjob:
$crontabe -e
* * * * * /home/script.sh
if you need to refresh in less than a minute you can use the command "sleep" inside your script.
I have a historical autogenerated logfile with the following format that I would like to convert to a csv file prior to uploading to a database
--------------------------------------
Thu Jul 8 09:34:12 BST 2010
BLUE Head 1
Duration = 20 s
Activity = 14.9 MBq
Sensitivity = 312 cps/MBq
--------------------------------------
Thu Jul 8 09:34:55 BST 2010
BLUE Head 1
Duration = 20 s
Activity = 14.9 MBq
Sensitivity = 318 cps/MBq
--------------------------------------
Thu Jul 8 10:13:39 BST 2010
RED Head 1
Duration = 20 s
Activity = 14.9 MBq
Sensitivity = 307 cps/MBq
--------------------------------------
Thu Jul 8 10:14:10 BST 2010
RED Head 1
Duration = 20 s
Activity = 14.9 MBq
Sensitivity = 305 cps/MBq
--------------------------------------
Mon Jul 19 10:11:18 BST 2010
BLUE Head 1
Duration = 20 s
Activity = 12.4 MBq
Sensitivity = 326 cps/MBq
--------------------------------------
Mon Jul 19 10:12:09 BST 2010
BLUE Head 1
Duration = 20 s
Activity = 12.4 MBq
Sensitivity = 333 cps/MBq
--------------------------------------
Mon Jul 19 10:13:57 BST 2010
RED Head 1
Duration = 20 s
Activity = 12.4 MBq
Sensitivity = 338 cps/MBq
--------------------------------------
Mon Jul 19 10:14:45 BST 2010
RED Head 1
Duration = 20 s
Activity = 12.4 MBq
Sensitivity = 340 cps/MBq
--------------------------------------
I would like to convert the logfile to the following format
Date,Camera,Head,Duration,Activity
08/07/10,BLUE,1,20,14.9
08/07/10,BLUE,1,20,14.9
08/07/10,RED,1,20,14.9
08/07/10,RED,1,20,14.9
I have used awk to get me close to what I wish
awk 'BEGIN {print "Date,Camera,Head,Duration,Activity";RS = "--------------------------------------"; FS="\n";}; {OFS=",";split($3, a, " ");split($4,b, " "); split($5,c," ");print $2,a[1],a[3],b[3],c[3]}' sensitivity.txt > sensitivity.csv
which gives me
Date,Camera,Head,Duration,Activity
,,,,
Thu Jul 8 09:34:12 BST 2010,BLUE,1,20,14.9
Thu Jul 8 09:34:55 BST 2010,BLUE,1,20,14.9
Thu Jul 8 10:13:39 BST 2010,RED,1,20,14.9
Thu Jul 8 10:14:10 BST 2010,RED,1,20,14.9
How can I
(a) get rid of the 4 output field separators in line 4
(b) Convert the date format from Thu Jul 8 09:34:12 BST 2010 to DD/MM/YY (Can I do this in pure awk or by piping to perl)
#sudo_O's answer is fine but here's an alternative:
$ cat tst.awk
BEGIN{ RS="---+\n"; OFS=","; months="JanFebMarAprMayJunJulAugSepOctNovDec" }
NR==1{ print "Date","Camera","Head","Duration","Activity"; next }
{ print sprintf("%04d%02d%02d",$6,(match(months,$2)+2)/3,$3),$7,$9,$12,$16 }
$ gawk -f tst.awk file
Date,Camera,Head,Duration,Activity
20100708,BLUE,1,20,14.9
20100708,BLUE,1,20,14.9
20100708,RED,1,20,14.9
20100708,RED,1,20,14.9
20100719,BLUE,1,20,12.4
20100719,BLUE,1,20,12.4
20100719,RED,1,20,12.4
20100719,RED,1,20,12.4
Note that I used GNU awk above so I could set the RS to more than a single character. With other awks just convert all the "---..."s lines to a blank line or control character or something and set RS accordingly before running the script.
If you don't like my suggested date format, tweak the sprintf() to suit.
This straight forward awk script will do the job:
BEGIN {
n=split("Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec",month,"|")
for (i=1;i<=n;i++) {
month_index[month[i]] = i
}
print "Date,Camera,Head,Duration,Activity"
}
/^-*$/{
i=0
next
}
{
i++
}
i==1{
printf "%02d/%02d/%02d,",$3,month_index[$2],substr($6,3)
}
i==2{
printf "%s,%d,",$1,$3
}
i==3{
printf "%d,",$3
}
i==4{
printf "%.1f\n",$3
}
Outputs:
$ awk -f script.awk file
08/07/10,BLUE,1,20,14.9
08/07/10,BLUE,1,20,14.9
08/07/10,RED,1,20,14.9
08/07/10,RED,1,20,14.9
19/07/10,BLUE,1,20,12.4
19/07/10,BLUE,1,20,12.4
19/07/10,RED,1,20,12.4
19/07/10,RED,1,20,12.4
I figured I would show how to actually parse the input, rather than just performing string transformations.
#! /usr/bin/env perl
use strict;
use warnings;
use Date::Parse;
use Date::Format;
use Text::CSV;
sub convert_date{
my $time = str2time($_[0]);
# iso 8601 style:
return time2str('%Y-%m-%d',$time); # YYYY-MM-DD
# or the outdated style output you wanted
return time2str('%d/%m/%y',$time); # DD/MM/YY
}
my %multiply_table = (
s => 1,
m => 60,
h => 60 * 60,
d => 60 * 60 * 24,
);
sub convert_duration{
my($d,$s) = $_[0] =~ /^ \s* (\d+) \s* (\w) \s* $/x;
die "Invalid duration '$_[0]'" unless $d && $s;
return $d * $multiply_table{$s};
}
my #field_list = qw'Date Camera Head Duration Activity';
my $csv = Text::CSV->new( { eol => "\n" } );
# print header
$csv->print( \*STDOUT, \#field_list );
# set record separator
local $/ = ('-' x 38) . "\n";
# parse data
while(<>){
chomp; # remove record separator
next unless $_; # skip empty section
my($time,$camdat,#fields) = split m/\n/; # split up the fields
my %data;
# split camera and head fields
#data{qw(Camera Head)} = split /\s+Head\s+/, $camdat;
# parse lines like:
# Duration = 20 s
# Activity = 14.9 MBq
# Sensitivity = 305 cps/MBq
for(#fields){
my($key,$value) = /(\w+) \s* = \s* (.*) /x;
$data{$key} = $value;
}
# at this point we start reducing precision
$data{Date} = convert_date( $time );
# remove measurement units
$data{Duration} = convert_duration($data{Duration}); # safe
$data{Activity} =~ s/[^\d]*$//; # unsafe
$csv->print(\*STDOUT, [#data{#field_list}]);
}
I have "cvs diff" output (for all files in project) in unified diff format.
Format could be like this:
Index: somefile.cpp
===================================================================
RCS file: /CVS_repo/SomeProject/somefile.cpp,v
retrieving revision 1.19
diff -r1.19 somefile.cpp
31c31
< return "Read line four times";
---
> return "Read line five times";
36c36
< return "Make a bad thing";
---
> return "Make a good thing";
Index: otherfile.cpp
===================================================================
RCS file: /CVS_repo/SomeProject/otherfile.cpp,v
retrieving revision 1.19
< ........
---
> ........
or even like this:
Index: somefile.cpp
===================================================================
RCS file: /CVS_repo/SomeProject/somefile.cpp,v
retrieving revision 1.19
diff -u -r1.19 somefile.cpp
--- somefile.cpp 13 Mar 2013 08:45:18 -0000 1.19
+++ somefile.cpp 26 Mar 2013 08:10:33 -0000
## -28,12 +28,12 ##
//---------------------------------------------------------------------------
extern "C" char *FuncGetSomeText()
{
- return "Read line four times";
+ return "Read line five times";
}
//---------------------------------------------------------------------------
extern "C" char *FuncGetAwesomeText()
{
- return "Make a bad thing";
+ return "Make a good thing";
}
//---------------------------------------------------------------------------
Index: otherfile.cpp
===================================================================
RCS file: /CVS_repo/SomeProject/otherfile.cpp,v
retrieving revision 1.19
diff -u -r1.19 otherfile.cpp
--- otherfile.cpp 13 Mar 2013 08:45:18 -0000 1.19
+++ otherfile.cpp 26 Mar 2013 08:10:33 -0000
## -28,12 +28,12 ##
//---------------------------------------------------------------------------
extern "C" char *Func()
{
- .......
+ .......
}
//---------------------------------------------------------------------------
Is there any way to view this text side-by-side with vim?
Or maybe it's possible to change default diff tool in cvs to vimdiff?
Some sed magic help me:
\cvs -n diff -u > ~diff.tmp; vim -O <(sed -r -e 's/^\+[^\+]+.*$//g;s/^\+$//g' ~diff.tmp) <(sed -r -e 's/^-[^-]+.*$//g;s/^-$//g' ~diff.tmp) +'set scb | set nowrap | wincmd w | set scb | set nowrap'
It is not perfect solution, but better then nothing. Here what this script doing:
\cvs -n diff -u > ~diff.tmp;
Write CVS diff output in unified format (-u option) to temp file ~diff.tmp. '\' char prevent from taking alias of "cvs" command.
(sed -r -e 's/^\+[^\+]+.*$//g;s/^\+$//g' ~diff.tmp)
(sed -r -e 's/^-[^-]+.*$//g;s/^-$//g' ~diff.tmp)
This commands output text from ~diff.tmp, replace lines beginning with '+' and '-' symbols with empty line.
vim -O <(sed...) <(sed...) +'set scb | set nowrap | wincmd w | set scb | set nowrap'
Open two windows (-O option) with sed's output in each. Command followed '+' set srollbind on and nowrap for first window, then switch to second window (with 'wincmd w') and do same things
Is there a limit to the amount of data that can be stored in an environment variable on Linux, and if so: what is it?
For Windows, I've found following KB article which summarizes to:
Windows XP or later: 8191 characters
Windows 2000/NT 4.0: 2047 characters
I don't think there is a per-environment variable limit on Linux. The total size of all the environment variables put together is limited at execve() time. See "Limits on size of arguments and environment" here for more information.
A process may use setenv() or putenv() to grow the environment beyond the initial space allocated by exec.
Here's a quick and dirty program that creates a 256 MB environment variable.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
int main(void)
{
size_t size = 1 << 28; /* 256 MB */
char *var;
var = malloc(size);
if (var == NULL) {
perror("malloc");
return 1;
}
memset(var, 'X', size);
var[size - 1] = '\0';
var[0] = 'A';
var[1] = '=';
if (putenv(var) != 0) {
perror("putenv");
return 1;
}
/* Demonstrate E2BIG failure explained by paxdiablo */
execl("/bin/true", "true", (char *)NULL);
perror("execl");
printf("A=%s\n", getenv("A"));
return 0;
}
Well, it's at least 4M on my box. At that point, I got bored and wandered off. Hopefully the terminal output will be finished before I'm back at work on Monday :-)
export b1=A
export b2=$b1$b1
export b4=$b2$b2
export b8=$b4$b4
export b16=$b8$b8
export b32=$b16$b16
export b64=$b32$b32
export b128=$b64$b64
export b256=$b128$b128
export b512=$b256$b256
export b1k=$b512$b512
export b2k=$b1k$b1k
export b4k=$b2k$b2k
export b8k=$b4k$b4k
export b16k=$b8k$b8k
export b32k=$b16k$b16k
export b64k=$b32k$b32k
export b128k=$b64k$b64k
export b256k=$b128k$b128k
export b512k=$b256k$b256k
export b1m=$b512k$b512k
export b2m=$b1m$b1m
export b4m=$b2m$b2m
echo $b4m
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
: : : : : : : : : : : :
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
If you're worried that 4M may not be enough for your environment variable, you may want to rethink how you're doing things.
Perhaps it would be a better idea to put the information into a file and then use an environment variable to reference that file. I've seen cases where, if the variable is of the form #/path/to/any/fspec, it gets the actual information from the file path/to/any/fspec. If it doesn't begin with #, it uses the value of the environment variable itself.
Interestingly enough, with all those variables set, every single command starts complaining that the argument list is too long so, even though it lets you set them, it may not be able to start programs after you've done it (since it has to pass the environment to those programs).
Here are two helpful commands:
getconf -a | grep ARG_MAX
true | xargs --show-limits
I did a quick test on my Linux box with the following snippet:
a="1"
while true
do
a=$a$a
echo "$(date) $(numfmt --to=iec-i --suffix=B --padding=7 ${#a})"
done
On my box (Gentoo 3.17.8-gentoo-r1) this results in (last lines of output):
Wed Jan 3 12:16:10 CET 2018 16MiB
Wed Jan 3 12:16:11 CET 2018 32MiB
Wed Jan 3 12:16:12 CET 2018 64MiB
Wed Jan 3 12:16:15 CET 2018 128MiB
Wed Jan 3 12:16:21 CET 2018 256MiB
Wed Jan 3 12:16:33 CET 2018 512MiB
xrealloc: cannot allocate 18446744071562068096 bytes
So: the limit is quite high!
Don't know exactly but a quick experiment shows that no error occurs e.g. with 64kB of value:
% perl -e 'print "#include <stdlib.h>\nint main() { return setenv(\"FOO\", \"", "x"x65536, "\", 1); }\n";'\
| gcc -x c -o envtest - && ./envtest && echo $?
0
I used this very quick and dirty php code (below), modifying it for different values, and found that it works for variable lengths up to 128k. After that, for whatever reason, it doesn't work; no exception is raised, no error is reported, but the value does not show up in the subshell.
Maybe this is a php-specific limit? Maybe there are php.ini settings that might affect it? Or maybe there's a limit on the size of vars that a subshell will inherit? Maybe there are relevant kernel or shell config settings..
Anyway, by default, in CentOS, the limit for setting a var in the environment via putenv in php seems to be about 128k.
<?php
$s = 'abcdefghijklmnop';
$s2 = "";
for ($i = 0; $i < 8100; $i++) $s2 .= $s;
$result = putenv('FOO='.$s2);
print shell_exec('echo \'FOO: \'${FOO}');
print "length of s2: ".strlen($s2)."\n";
print "result = $result\n";
?>
Version info -
[root#localhost scratch]# php --version
PHP 5.2.6 (cli) (built: Dec 2 2008 16:32:08)
<..snip..>
[root#localhost scratch]# uname -a
Linux localhost.localdomain 2.6.18-128.2.1.el5 #1 SMP Tue Jul 14 06:36:37 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux
[root#localhost scratch]# cat /etc/redhat-release
CentOS release 5.3 (Final)
The command line (with all argument) plus the environment variable should be less then 128k.
In my case it was due to buffer was limited when accepting a variable input value with read command. Solution was to add -e
Before read accessToken
After read -e accessToken
Docs: http://linuxcommand.org/lc3_man_pages/readh.html