Unnecessary bash warning message
### Machine: x86_64 OS: linux-gnu Compiler: gcc Compilation CFLAGS: -g -O2 -flto=auto -ffat-lto-objects -flto=auto -ffat-lto-objects -fstack-protector-strong -Wformat -Werror=format-security -Wall uname output: Linux EliteBook 6.2.0-20-generic #20-Ubuntu SMP PREEMPT_DYNAMIC Thu Apr 6 07:48:48 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux Machine Type: x86_64-pc-linux-gnu Bash Version: 5.2 Patch Level: 15 Release Status: release ### Process substitution can be used in place of a file in a command line as follows: bash$ cat test.jl for a in ARGS println(a) end bash$ julia test.jl 11 22 33 11 22 33 bash$ julia <( cat <<\@ for a in ARGS println(a) end @ ) 11 22 33 11 22 33 However, in the above method, the 11 22 33 arguments are placed at the end of the command line, which is not good for readability. So writing the following would make the command line much more readable, but it would output unnecessary warning messages. bash$ julia <( cat <<\@ ) 11 22 33 for a in ARGS println(a) end @ bash: warning: command substitution: 1 unterminated here-document 11 22 33
regex string ">(...)" in [[ ]] command recognize as process substitution
##
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -g -O2 -flto=auto -ffat-lto-objects -flto=auto
-ffat-lto-objects -fstack-protector-strong -Wformat
-Werror=format-security -Wall
uname output: Linux EliteBook 5.19.0-23-generic #24-Ubuntu SMP
PREEMPT_DYNAMIC Fri Oct 14 15:39:57 UTC 2022 x86_64 x86_64 x86_64
GNU/Linux
Machine Type: x86_64-pc-linux-gnu
Bash Version: 5.2
Patch Level: 2
Release Status: release
##
I don't know if this is really a bug or not.
but the regex string ">(...)" in [[ ]] command is recognized as
process substitution
when using "( )" parentheses.
# this all works fine #
val="delete unset"
bash$ regex='(.*) <[^>]*> (.*)'
bash$ [[ $val =~ $regex ]] && echo yes
yes
bash$ [[ $val =~ (.*)\ \<[^\>]*\>\ (.*) ]] && echo yes
yes
bash$ [[ $val =~ ((.*) <[^>]*> (.*)) ]] && echo yes
yes
remove spaces in regex string ##
bash$ regex='(.*)<[^>]*>(.*)'
bash$ [[ $val =~ $regex ]] && echo yes
yes
bash$ [[ $val =~ (.*)\<[^\>]*\>(.*) ]] && echo yes
yes
# this is an error
# [[ ]] command recognizes ">(.*)" as process substitution.
bash$ [[ $val =~ ((.*)<[^>]*>(.*)) ]] && echo yes # Error !
bash$ .*: command not found
^C
# if i escape \> then the error goes away
bash$ [[ $val =~ ((.*)<[^>]*\>(.*)) ]] && echo yes # Ok
yes
The Second problem #
This only happens in the terminal.
# 1. intentionally makes an error by removing escape "\>" to ">"
bash$ [[ $val =~ (.*)\ \<[^\>]*>\ (.*) ]] && echo yes
bash: syntax error in conditional expression: unexpected token `>'
# 2. fixed the error with \> escape, but the error continues
bash$ [[ $val =~ (.*)\ \<[^\>]*\>\ (.*) ]] && echo yes
bash: syntax error near unexpected token `$val'
# 3. On the second try, the error goes away.
bash$ [[ $val =~ (.*)\ \<[^\>]*\>\ (.*) ]] && echo yes
yes
The third problem #
This also happens only in the terminal.
but very unexpectedly happens
# 1. command executed successfully
bash$ [[ $val =~ (.*)\ \<[^\>]*\>\ (.*) ]] && echo yes
yes
# 2. but the output of the ${BASH_REMATCH[1]} variable is incorrect.
bash$ echo ${BASH_REMATCH[1]}
${ # or something like "${BASH_RE"
bash$ echo ${BASH_REMATCH[1]}
${
# 3. if i try again, it outputs normally.
bash$ [[ $val =~ (.*)\ \<[^\>]*\>\ (.*) ]] && echo yes
yes
bash$ echo ${BASH_REMATCH[1]}
delete
bash "extglob" needs to upgrade at least like zsh "kshglob"
##
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -g -O2 -flto=auto -ffat-lto-objects -flto=auto
-ffat-lto-objects -fstack-protector-strong -Wformat
-Werror=format-security -Wall
uname output: Linux EliteBook 5.19.0-23-generic #24-Ubuntu SMP
PREEMPT_DYNAMIC Fri Oct 14 15:39:57 UTC 2022 x86_64 x86_64 x86_64
GNU/Linux
Machine Type: x86_64-pc-linux-gnu
Bash Version: 5.2
Patch Level: 2
Release Status: release
##
bash "extglob" almost unusable except with very tiny string.
there is no such problems in zsh "kshglob".
# this is just for testing purposes.
$ foo=$( gcc -v --help 2> /dev/null | sed -En 's/^\s*(-[^ ]+).*/\1/p' )
# this is a simple work that just removes trailing spaces.
( in bash )$ time res=${foo%%+( )}
real0m10.409s # 10 seconds !
user0m10.408s
sys 0m0.000s
( in zsh )$ setopt kshglob
( in zsh )$ res=${foo%%+( )}"
Done immediately.
( in bash )$ res=${foo//*( )$'\n'*( )/$'\n'}
No hope
( in zsh )$ res=${foo//*( )$'\n'*( )/$'\n'}
Done almost immediately.
Parameter expansion with extended pattern make system hang
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -g -O2 -flto=auto -ffat-lto-objects -flto=auto
-ffat-lto-objects -fstack-protector-strong -Wformat
-Werror=format-security -Wall
uname output: Linux EliteBook 5.15.0-43-generic #46-Ubuntu SMP Tue Jul
12 10:30:17 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu
Bash Version: 5.1
Patch Level: 16
Release Status: release
##
"gcc --help" is already a short string, but the system hangs.
( without using extended pattern, there is no such problem )
bash$ help=$( gcc --help )
bash$ echo "${help//+([$' \t\n'])/ }"
It barely works for very short strings only. (so almost can not use)
bash$ help=$( gcc --help | sed -n '1, 10p' )
bash$ echo "${help//+([$' \t\n'])/ }"
Usage: gcc [options] file... Options: -pass-exit-codes Exit with highest
error code from a phase. --help Display this information. --target-help
Display target specific command line options.
--help={common|optimizers|params|target|warnings|[^]{joined|separate|undocumented}}[,...].
Display specific types of command line options. (Use '-v --help' to
display command
line options of sub-processes). --version Display compiler version information.
-dumpspecs Display all of the built in spec strings.
bash command completion has a problem with sudo command
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -g -O2 -flto=auto -ffat-lto-objects -flto=auto
-ffat-lto-objects -fstack-protector-strong -Wformat
-Werror=format-security -Wall
uname output: Linux EliteBook 5.15.0-43-generic #46-Ubuntu SMP Tue Jul
12 10:30:17 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu
Bash Version: 5.1
Patch Level: 16
Release Status: release
##
when command completion function start running there are three
variables automatically setting
bash$ hello foo ba[tab]
$1 (command): hello
$2 (current):ba
$3 (previous): foo
bash$ echo -n "$COMP_WORDBREAKS" | od -a
000 sp ht nl " ' @ > < = ; | & ( :
bash$ hello --opt foo:[tab]# ":" is a member of $COMP_WORDBREAKS
$1 (command): hello
$2 (current):(empty) # default behavior
$3 (previous): foo
bash$ sudo hello --opt foo:[tab] # using sudo command
$1 (command): hello
$2 (current):: <- not empty
$3 (previous): foo
In cases where the $2 variable's value is a member of the
$COMP_WORDBREAKS variable
then the $2 value is empty by default and has to use the
${COMP_WORDS[COMP_CWORD]} variable for that value.
I think this is good for making the completion function simpler.
but if I use the sudo command in front of the hello command then the
$2 value is not empty.
this ends up can not use $2 variable and force to use
${COMP_WORDS[COMP_CWORD]} variable
read built-in command has a problem in shell function
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -g -O2 -flto=auto -ffat-lto-objects
-fstack-protector-strong -Wformat -Werror=format-security -Wall
uname output: Linux EliteBook 5.11.0-25-generic #27-Ubuntu SMP Fri Jul
9 23:06:29 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu
Bash Version: 5.1
Patch Level: 4
Release Status: release
###
If i want to know whether there are input available from stdin
then i use "read -t 0" command like this
if read -t 0; then# first check input available
while read line; do ... done
...
fi
this command works well in *shell script file*
but in shell function does not work well
sh$ myfunc() { if read -t 0; then echo yes; fi ;}
sh$ myfunc <<\EOF# OK
111
EOF
yes
sh$ myfunc <<< 111 # OK
yes
sh$ echo 111 | myfunc# OK
yes
sh$ cat foo.c | myfunc# NOT WORK!
sh$ date | myfunc # NOT WORK!
if i change like this. then this time work well
sh$ date | { date > /dev/null; myfunc ;}
yes
bash command alias has a problem in using brace.
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -g -O2 -flto=auto -ffat-lto-objects
-fstack-protector-strong -Wformat -Werror=format-security -Wall
uname output: Linux EliteBook 5.11.0-25-generic #27-Ubuntu SMP Fri Jul
9 23:06:29 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu
Bash Version: 5.1
Patch Level: 4
Release Status: release
###
If i enter a command line like below then '>' prompt appears for the
input of here document.
bash$ { cat <<\@ > foo ;} 2> /dev/null
> 111
> 222 # '>' prompt
> @
but if i use alias then '>' prompt does not appear and default bash
prompt appears
bash$ alias myalias='{ cat <<\@ > foo ;} 2> /dev/null'
bash$ myalias
bash$ 111
bash$ 222 # bash$ prompt
bash$ @
this only occurs in brace
bash$ alias myalias='( cat <<\@ > foo ) 2> /dev/null'
bash$ myalias
> 111
> 222 # '>' prompt
> @
Re: Arithmetic pow results incorrect in arithmetic expansion.
I didn't know that all other shells work the same.
Thanks for the clarification.
2021년 1월 9일 (토) 오후 2:29, Lawrence Velázquez 님이 작성:
> > On Jan 8, 2021, at 11:19 PM, Hyunho Cho wrote:
> >
> > Machine: x86_64
> > OS: linux-gnu
> > Compiler: gcc
> > Compilation CFLAGS: -g -O2
> > -fdebug-prefix-map=/build/bash-a6qmCk/bash-5.0=.
> > -fstack-protector-strong -Wformat -Werror=format-security -Wall
> > -Wno-parentheses -Wno-format-security
> > uname output: Linux EliteBook 5.4.0-42-generic #46-Ubuntu SMP Fri Jul
> > 10 00:24:02 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
> > Machine Type: x86_64-pc-linux-gnu
> >
> > Bash Version: 5.0
> > Patch Level: 17
> > Release Status: release
> >
> >
> >
> > i have tested below in gnome calculator, Qalculate, gawk, perl
> > and all results in -4 but bash is 4
> >
> > $ awk 'BEGIN { print -2 ^ 2 }'
> > -4
> >
> > $ perl -E 'say -2 ** 2'
> > -4
> >
> > $ echo $(( -2 ** 2 )) # only bash results in 4
> > 4
>
> The bash results disagree with awk and perl (and, admittedly, common
> mathematical convention), but the man page clearly states that unary
> minus has higher precedence than exponentiation, so this behavior
> is intentional.
>
> The operators and their precedence, associativity, and values are
> the same as in the C language. The following list of operators is
> grouped into levels of equal-precedence operators. The levels are
> listed in order of decreasing precedence.
>
> id++ id-- variable post-increment and post-decrement
> - + unary minus and plus
> ++id --id variable pre-increment and pre-decrement
> ! ~ logical and bitwise negation
> ** exponentiation
> [remaining operators follow]
>
> Additionally, this precedence is consistent with other shells.
>
> % bash --version | head -n 1
> GNU bash, version 5.0.17(1)-release (x86_64-apple-darwin18.7.0)
> % bash -c 'printf %s\\n "$((-2 ** 2))"'
> 4
>
> % ksh --version
> version sh (AT&T Research) 93u+ 2012-08-01
> % ksh -c 'printf %s\\n "$((-2 ** 2))"'
> 4
>
> % zsh --version
> zsh 5.8 (x86_64-apple-darwin18.7.0)
> % zsh -fc 'printf %s\\n "$((-2 ** 2))"'
> 4
> % zsh -f -o C_PRECEDENCES -c 'printf %s\\n "$((-2 ** 2))"'
> 4
>
> The zshmisc(1) man page even goes out of its way to address this.
>
> Note the precedence of exponentiation in both cases is below that of
> unary operators, hence `-3**2' evaluates as `9', not `-9'. Use
> parentheses where necessary: `-(3**2)'. This is for compatibility
> with other shells.
>
> I don't know why things shook out this way, but it sure seems like
> the ship has sailed.
>
> vq
>
Arithmetic pow results incorrect in arithmetic expansion.
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -g -O2
-fdebug-prefix-map=/build/bash-a6qmCk/bash-5.0=.
-fstack-protector-strong -Wformat -Werror=format-security -Wall
-Wno-parentheses -Wno-format-security
uname output: Linux EliteBook 5.4.0-42-generic #46-Ubuntu SMP Fri Jul
10 00:24:02 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu
Bash Version: 5.0
Patch Level: 17
Release Status: release
i have tested below in gnome calculator, Qalculate, gawk, perl
and all results in -4 but bash is 4
$ awk 'BEGIN { print -2 ^ 2 }'
-4
$ perl -E 'say -2 ** 2'
-4
$ echo $(( -2 ** 2 )) # only bash results in 4
4
Problems with command substitution and command alias
Machine: x86_64 OS: linux-gnu Compiler: gcc Compilation CFLAGS: -g -O2 -fdebug-prefix-map=/build/bash-a6qmCk/bash-5.0=. -fstack-protector-strong -Wformat -Werror=format-security -Wall -Wno-parentheses -Wno-format-security uname output: Linux EliteBook 5.4.0-42-generic #46-Ubuntu SMP Fri Jul 10 00:24:02 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux Machine Type: x86_64-pc-linux-gnu Bash Version: 5.0 Patch Level: 17 Release Status: release ### ### 1. if command does not exist then the command stop with "command not found" error but the command substitution executed completely if i run following command ( including "prompt$" ) then "command not found" error occurred but "$( mktemp -d -p /dev/shm )" command substitution executed completely prompt$ cd $(mktemp -d -p /dev/shm) && ( curl -L https://ftp.gnu.org/gnu/bash/bash-5.1-rc3.tar.gz | tar xvz && cd bash-5.1-rc3 && ./configure && make -j `nproc` && strip bash ) && mv bash-5.1-rc3/bash "$OLDPWD" && rm -rf "$PWD" && cd - bash-5.0: prompt$: command not found $ ls -l /dev/shm/ total 0 drwx-- 2 mug896 mug896 40 2020-11-21 23:22 tmp.WK0k0MWZ2n/ --- ### 2. alias-expand-line readline function affects not only command line but also heredoc contents if i set up a command alias like below. it works well as expected. $ alias foo='make -f- << "EOF" 2> /dev/null' $ foo foo := 100 $(info $(foo)) EOF 100 # result but if i hit a key that is bound to alias-expand-line readline function for add more command line options of make then foo is expanded not only in command line but also in heredoc contents $ make -f- << "EOF" 2> /dev/null make -f- << "EOF" 2> /dev/null := 100 $(info $(make -f- << "EOF" 2> /dev/null)) EOF
problem with using ctrl-x ctrl-e ( open vi editor )
Machine: x86_64 OS: linux-gnu Compiler: gcc Compilation CFLAGS: -g -O2 -fdebug-prefix-map=/build/bash-a6qmCk/bash-5.0=. -fstack-protector-strong -Wformat -Werror=format-security -Wall -Wno-parentheses -Wno-format-security uname output: Linux EliteBook 5.4.0-42-generic #46-Ubuntu SMP Fri Jul 10 00:24:02 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux Machine Type: x86_64-pc-linux-gnu Bash Version: 5.0 Patch Level: 17 Release Status: release # bash$ cat <<\EOF # without using ctrl-x ctrl-e there is no problem occurred. > 111 > 222 > EOF 111 222 --- bash$ cat <<\EOF > 111 > < in this line open vi editor with ctrl-x ctrl-e and add another 222 line then :wq bash$ cat <<\EOF > 111 > cat <<\EOF 111 222 EOF 111< successfully executed cat command with heredoc 222 > > > > ^C < but does not end ">" prompt until enter ctrl-c
Commands that work in bash-5.0 but not in bash-5.1-rc1
< bash-5.0 >
bash$ echo hello | cat <(cat) > >(tr a-z A-Z)
HELLO
< bash-5.1-rc1 >
bash$ echo hello | cat <(cat) > >(tr a-z A-Z)
<-- empty
---
< bash-5.0 >
bash$ cat <<\@ | gcc -fPIC -shared -Wl,--version-script=<(cat) -o
libfoo.so foo.c
LIBFOO_1.0 {
global:
libfoo_init; libfoo_doit; libfoo_done;
local:
*;
};
@
< bash-5.1-rc1 >
bash$ cat <<\@ | gcc -fPIC -shared -Wl,--version-script=<(cat) -o
libfoo.so foo.c
LIBFOO_1.0 {
global:
libfoo_init; libfoo_doit; libfoo_done;
local:
*;
};
@
/usr/bin/ld:/dev/fd/63:0: syntax error in VERSION script
< Error occurred
collect2: error: ld returned 1 exit status
background process in command substitution
There are cases that need not wait until background process finish -- In this case, zsh and bash wait 3 seconds to finish the assignment operation. because sleep command's STDOUT is the pipe of command substitution. < zsh > $ AA=$( sleep 3 & date )# wait 3 seconds to finish < bash > $ AA=$( sleep 3 & date )# same as zsh In this case, sleep command's STDOUT is redirected to FD 3 so there is no needs to wait 3 seconds zsh return immediately with the value of background process PID but bash still waits 3 seconds to finish the assignment operation. < zsh > $ exec 3>&1 $ PID=$( date > >( sleep 3 >&3 ) & echo $! ) < bash > $ exec 3>&1 $ PID=$( date > >( sleep 3 >&3 ) & echo $! )
Things that work in bash-5.0 but not work in bash-5.1-rc1
< bash-5.0 > $ read rows cols < <(stty size) $ echo $rows $cols 19 95 < bash-5.1-rc1 > $ read rows cols < <(stty size) stty: 'standard input': Inappropriate ioctl for device $ echo $rows $cols < empty --- < bash-5.0 > # emacs start with contents of ls command output $ ls | emacs < /dev/tty --insert <(cat) < bash-5.1-rc1 > # emacs does not start with contents of ls command output $ ls | emacs < /dev/tty --insert <(cat) --- < bash-5.0 > $ ( trap 'uname' CHLD; date ) Wed Oct 7 16:39:55 KST 2020 Linux < bash-5.1-rc1 > $ ( trap 'uname' CHLD; date ) # some strange warning messages appear Wed Oct 7 16:40:05 KST 2020 Linux bash: warning: run_pending_traps: recursive invocation while running trap for signal 17
coproc does not work in subshell
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -g -O2
-fdebug-prefix-map=/build/bash-a6qmCk/bash-5.0=.
-fstack-protector-strong -Wformat -Werror=format-security -Wall
-Wno-parentheses -Wno-format-security
uname output: Linux EliteBook 5.4.0-42-generic #46-Ubuntu SMP Fri Jul
10 00:24:02 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu
Bash Version: 5.0
Patch Level: 17
Release Status: release
bash$ coproc while read -r line; do eval expr "$line"; done
[1] 172053
bash$ echo "1 + 2" >& ${COPROC[1]}; read -r <& ${COPROC[0]}; echo
$REPLY # OK
3
bash$ echo $( echo "1 + 3" >& ${COPROC[1]}; read -r <& ${COPROC[0]};
echo $REPLY ) # command substitution : OK
4
bash$ cat <( echo "1 + 4" >& ${COPROC[1]}; read -r <& ${COPROC[0]};
echo $REPLY ) # process substitution : OK
5
bash$ ( echo "1 + 5" >& ${COPROC[1]}; read -r <& ${COPROC[0]}; echo
$REPLY ) # ERROR : subshell does not work
bash: ${COPROC[1]}: Bad file descriptor
bash: ${COPROC[0]}: Bad file descriptor
3
multi-line command history does not work when new terminal opened
Machine: x86_64 OS: linux-gnu Compiler: gcc Compilation CFLAGS: -g -O2 -fdebug-prefix-map=/build/bash-a6qmCk/bash-5.0=. -fstack-protector-strong -Wformat -Werror=format-security -Wall -Wno-parentheses -Wno-format-security uname output: Linux EliteBook 5.4.0-42-generic #46-Ubuntu SMP Fri Jul 10 00:24:02 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux Machine Type: x86_64-pc-linux-gnu Bash Version: 5.0 Patch Level: 17 Release Status: release I have enabled the shell options for multi-line command history like this shopt -s lithist shopt -s cmdhist and it works well in current terminal bash$ history 8651 echo history test 1 8652 echo history test 2 8653 echo history test 3 8654 cat << EOF 111 222 # multi-line command history works well 333 EOF 8655 history --- if i opened new terminal then the multi-line commands all changed to single lines like this bash$ history 7819 echo history test 1 7820 echo history test 2 7821 echo history test 3 7822 cat << EOF 7823 111 # the multi-line commands changed to single lines 7824 222 7825 333 7826 EOF 7827 history
heredoc seems to parse contents even with the quoted delimiter in shell prompt
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -g -O2
-fdebug-prefix-map=/build/bash-a6qmCk/bash-5.0=.
-fstack-protector-strong -Wformat -Werror=format-security -Wall
-Wno-parentheses -Wno-format-security
uname output: Linux EliteBook 5.4.0-42-generic #46-Ubuntu SMP Fri Jul
10 00:24:02 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu
Bash Version: 5.0
Patch Level: 17
Release Status: release
if i use "test.sh" file for running shell script like this, there are
no error messages appear
bash$ cat test.sh
#!/bin/bash
cat << "EOF"
this is a test comment
$(info $(foo ${bar)))
EOF
bash$ ./test.sh # no error messages appear
this is a test comment
$(info $(foo ${bar)))
---
if i use the same script in shell prompt then strange error messages appear
bash$ cat << "EOF"
this is a test comment
$(info $(foo ${bar)))
EOF
bash: command substitution: line 798: unexpected EOF while looking for
matching `}'
bash: command substitution: line 799: syntax error: unexpected end of file
bash: command substitution: line 798: unexpected EOF while looking for
matching `}'
bash: command substitution: line 799: syntax error: unexpected end of file
this is a test comment
$(info $(foo ${bar)))
bash errexit shell option does not work in some cases.
GNU bash, version 5.0.16(1)-release (x86_64-pc-linux-gnu)
Operating System: Ubuntu 20.04 LTS
Kernel: Linux 5.4.0-33-generic
Architecture: x86-64
bash errexit shell option does not work in some cases.
after execution a command, exitcode is set to "1" but shell script does not
exited.
# WORK CASE ###
#!/bin/bash -e # errexit option
cat < not_exist.txt # not exist file
echo end
## result ##
$ ./test.sh # work as expected
./test.sh: line 3: not_exist.txt: No such file or directory
### NOT WORK CASES ###
#!/bin/bash -e
{ cat ;} < not_exist.txt
echo "exitcode : $?"
echo end
## result ##
$ ./test.sh
exitcode : 1 # exitcode is set to "1"
./test.sh: line 3: not_exist.txt: No such file or directory
end # but test.sh does not exited
--
#!/bin/bash -e
while read -r line; do
echo "$line"
done < not_exist.txt
echo "exitcode : $?"
echo end.
## result ##
$ ./test.sh
./test.sh: line 5: not_exist.txt: No such file or directory
exitcode : 1# exitcode is set to "1"
end.# but does not exited
$OPTIND varibale value is different from sh
if $OPTIND value start from 1 then i think "-b" $OPTIND should be "3" like sh but bash print "2" set -- -a -bc hello world echo $OPTIND# sh, bash = 1 getopts abc opt "$@" echo $opt, $OPTIND # sh, bash = a, 2 getopts abc opt "$@" # bash = b, 2 <-- different from "sh" echo $opt, $OPTIND# sh = b, 3 getopts abc opt "$@" # sh, bash = c, 3 echo $opt, $OPTIND
bash process substitution weird behavior
Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -DPROGRAM='bash' -DCONF_HOSTTYPE='x86_64'
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='x86_64-pc-linux-gnu'
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL
-DHAVE_CONFIG_H -I. -I../. -I.././include -I.././lib -D_FORTIFY_SOURCE=2 -g
-O2 -fstack-protector-strong -Wformat -Werror=format-security -Wall
uname output: Linux EliteBook 4.2.0-19-generic #23-Ubuntu SMP Wed Nov 11
11:39:30 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu
Bash Version: 4.3
Patch Level: 42
Release Status: release
Description:
1.
BASH$ { echo 111; echo 222 ;} 2> >( echo -en "\e[01;31m" >&2; read line; echo
"$line" >&2; echo -en "\e[0m" >&2 ) >&2
111# result is one line and red-colored that is expected behavior.
2.
# If i remove ">&2" that is at the end of command
# result is two lines with white-colored that is also expected behavior.
BASH$ { echo 111; echo 222 ;} 2> >( echo -en "\e[01;31m" >&2; read line; echo
"$line" >&2; echo -en "\e[0m" >&2 )
111# white colored
222# white colored
3.
# If i add external "date" command in the middle of two echo commands
# result is in red-colored after external date command output
# i think there must be no red-colored because { echo 111; date; echo 222 ;}
only direct to stdout
BASH$ { echo 111; date; echo 222 ;} 2> >( echo -en "\e[01;31m" >&2; read line;
echo "$line" >&2; echo -en "\e[0m" >&2 )
111 # white colored
Tue Dec 8 20:33:33 KST 2015 # red colored
222 # red colored
