I have a bash script that rsyncs my files to my remote server. I want to check if there are lines with "import ipdb;ipdb.set_trace()" before syncing, but I can't. This is my script:
#!/bin/bash;
var="$1" ;
if [ "$var" == "main" -o "$var" == "all" ] ; then
echo "*** checking of ipdb lines, first ***" ;
res=$(ack-grep --type=python "import ipdb" -c -l) ;
if [ $res ] ; then
echo $res ;
else
rsync -Paz --exclude ".*" -e "ssh -i /home/chris/.ssh/thishost-rsync-key" this_pc remote_pc
fi
fi
I always get this type of error:
*** checking of ipdb lines, first ***
sync.sh: line 10: [: too many arguments
sending incremental file list
Line 10 in my script is this one: if [ $res ] ; then
What am I doing wrong?
When you do
res=$(ack-grep --type=python "import ipdb" -c -l) ;
the variable $res is set to contain the output from the command(s) inside $(...).
If you want the resulting exit status use $? instead, otherwise use e.g.
if [ ! -z "$res" ] ...
to check if $res is not empty (meaning that there was output from the command).
Instead of :
if [ $res ] ; then
Use:
if [ ! -z "$res" ] ; then
-z => return True if the length of string is zero.
Related
I can't get my bash script (a logging file) to detect any other exit code other than 0, so the count for failed commands isn't being incremented, but the successes is incremented regardless of whether the command failed or succeeded.
Here is the code:
#!/bin/bash
#Script for Homework 8
#Created by Greg Kendall on 5/10/2016
file=$$.cmd
signal() {
rm -f $file
echo
echo "User Aborted by Control-C"
exit
}
trap signal 2
i=0
success=0
fail=0
commands=0
read -p "$(pwd)$" "command"
while [ "$command" != 'exit' ]
do
$command
((i++))
echo $i: "$command" >> $file
if [ "$?" -eq 0 ]
then
((success++))
((commands++))
else
((fail++))
((commands++))
fi
read -p "$(pwd)" "command"
done
if [ "$command" == 'exit' ]
then
rm -f $file
echo commands:$commands "(successes:$success, failures:$fail)"
fi
Any help would be greatly appreciated. Thanks!
That's because echo $i: "$command" is succeeding always.
The exit status $? in if [ "$?" -eq 0 ] is actually the exit status of echo, the command that is run immediately before the checking.
So do the test immediate after the command:
$command
if [ "$?" -eq 0 ]
and use echo elsewhere
Or if you prefer you don't need the $? check at all, you can run the command and check status within if alone:
if $command; then .....; else ....; fi
If you do not want to get the STDOUT and STDERR:
if $command &>/dev/null; then .....; else ....; fi
** Note that, as #Charles Duffy mentioned in the comment, you should not run command(s) from variables.
Your code is correctly counting the number of times that the echo $i: "$command" command fails. I presume that you would prefer to count the number of times that $command fails. In that case, replace:
$command
((i++))
echo $i: "$command" >> $file
if [ "$?" -eq 0 ]
With:
$command
code=$?
((i++))
echo $i: "$command" >> $file
if [ "$code" -eq 0 ]
Since $? captures the exit code of the previous command, it should be placed immediately after the command whose code we want to capture.
Improvement
To make sure that the value of $? is captured before any other command is run, Charles Duffy suggests placing the assignment on the same line as the command like so:
$command; code=$?
((i++))
echo $i: "$command" >> $file
if [ "$code" -eq 0 ]
This should make it less likely that any future changes to the code would separate the command from the capture of the value of $?.
I have written the following Linux shell script through snippits gleaned from the web (I'm very new to shell scripts), its purpose is to ensure only a single instance of a programme is run with the added option of specifying which workspace a programme will open to.
I'm sure much of the code could be better constructed, however it works with one bug, when some, like Thunderbird, are opened they ignore the workspace switch unless the workaround I've added is used, but why? and is there a better way?
The script uses wmctrl: sudo apt-get install wmctrl
Usage: single-switch programme_name [-ws(int)] where (int) is number of workspace (must exist), the -ws param must be the last listed
#!/bin/bash
if ! [ $1 ] ; then exit ; fi
if [ "?" = "$1" ] ; then
FILE=$(echo "$0" | rev | cut -d "/" -f1 | rev) # extract filename from path
echo "usage $FILE <program name> [-ws(int)]"
exit 1;
fi
TITLE=$1
NAME=""
for var in "$#"; do [ "$(echo ${var} | head -c3)" != '-ws' ] && NAME="$NAME $var" ; done # remove our param from command
ntharg() { shift $1 ; echo $1 ; }
PARAM=`ntharg $# "$#"` # get the last param
if [ "-ws" != "$(echo ${PARAM} | head -c3)" ]; then PARAM=-1 ; # check its ours
else
PARAM=$( echo "$PARAM" | egrep -o '[0-9]+' ) # get the number
PARAM=$((PARAM-1)) # decrement
fi
if [ $PARAM -ge 0 ] ; then
wmctrl -x -a "$TITLE" || ( wmctrl -s $PARAM && zenity --title="Launch $TITLE" --warning --text="$TITLE is starting" --timeout="1" ; $NAME )
# dummy message otherwise some (ie thunderbird) ignore switch
else
wmctrl -x -a "$TITLE" || $NAME & # no switch, just raise or run programme
fi
# Done.
#
I'm trying to run those scripts but I keep receiving errors messages:
1-
#!/bin/bash
filename=$1
if [ -f $filename ]
then
owner=`stat -c %U $filename`
grep $owner /etc/passwd
if [ $? -eq 0 ]; then
perm=`stat -c %a $filename | head -c 1`
if [ $perm -gt 3 ]; then
cat $filename | grep NOTE
fi
fi
fi
the error message is :
stat: missing operand Try `stat --help' for more information.
2-
#!/bin/bash
NoSum=$1
sum=0
echo "Please enter $NoSum values one at a time"
for (( i=1; i<=$NoSum; i++ ))
do
echo "Next Value?"
read num
let "a = $sum + $num"
sum=$a
done
echo "The sum is : $sum"
the error message is:
Please enter values one at a time ./scr3: line 6: ((: i<=: syntax
error: operand expected (error token is "<=") The sum is : 0
3-
#!/bin/bash
dir=$1
if [ -d $dir ]
then
perm=`stat -c %a $dir | head -c 1`
if [ $perm -gt 5 ]; then
cd $dir
for file in $dir/*
do
if ! [ -x "$file" ]
then
echo "$file"
fi
done
fi
fi
the error message is:
stat: missing operand Try `stat --help' for more information. ./scr4:
line 8: [: -gt: unary operator expected
any idea how to fix them ?
Nothing is wrong about the programs.You are not supplying the command line arguments.You must run it as
1 and 3:
./script.sh <filename>
2:
./script.sh <number>
$1 stands for the first command line argument
You need to quote variables in bash to prevent word-splitting issues, both in test brackets [] and most of the time in other use.
So your first script would be
#!/bin/bash
filename="$1"
if [ -f "$filename" ]
then
owner="`stat -c %U "$filename"`"
grep "$owner" /etc/passwd
if [ $? -eq 0 ]; then
perm="`stat -c %a "$filename" | head -c 1`"
if [ "$perm" -gt 3 ]; then
cat "$filename" | grep NOTE
fi
fi
fi
The others have similar erros
I have written a shell script for printing book:
#!/bin/sh
if [ -z "$1" ]
then
exit 1
fi
filename=$1
options=""
mode="color"
first=""
last=""
pages="All pages from"
shift
until [ -z "$1" ]
do
if [ $1 = "gray" -o $1 = "grey" -o $1 = "grayscale" -o $1 = "greyscale" ]
then
options=" -o ColorModel=KGray"
mode=$1
elif [ $1 = "from" ]
then
shift
first="$1"
elif [ $1 = "to" ]
then
shift
last="$1"
fi
shift
done
if [ $first -o $last ]
then
pages="Pages"
if [ $first ]
then
pages="$pages $first"
first=" -f $first"
else
pages="$pages 1"
fi
if [ $last ]
then
pages="$pages to $last"
last=" -l $last"
else
pages="$pages to last"
fi
pages="$pages from"
fi
echo -n "$pages $filename will be printed in $mode mode. If it's OK, put paper in your printer and press ENTER. Else press CTRL+C. "
read ack
pdftops$first$last -expand $filename - | psbook | psnup -2 > tmp.ps
psselect -o tmp.ps | lpr$options
echo -n "Wait for the end of printing, then take printed pages, put them back in printer to print on other side and press ENTER again."
read ack
psselect -e -r tmp.ps | lpr$options
rm tmp.ps
exit 0
When I saved this code to file "print-book" and ran it like:
print-book test.pdf gray
I got this:
Pages 1 to last from test.pdf will be printed in gray mode. If it's OK, put paper in your printer and press ENTER. Else press CTRL+C
i.e. condition "$first -o $last" was true. But if check "$first" and "$last" separately in this place, they both are false.
How is this possible?
If $first and $last are empty, [ $first -o $last ] will be evaluated as [ -o ], which is not what you want.
You should instead use [ "$first" -o "$last" ], which is equivalent to [ "" -o "" ].
Never use variables without quoting them (unless you know what you're doing): the results will be unexpected most of the times.
Also, test weird behaviors interactively in the command line: just input [ $a -o $b ] && echo y to quickly see what's going on and being able to play with your variables.
I need to teach myself bash scripting. I'm reading this ebook and it has the following code:
#!/bin/bash
# hello.sh
# This is my first shell script!
declare -rx SCRIPT="hello.sh"
declare -rx who="/usr/bin/who"
declare -rx sync="/bin/sync"
declare -rx wc="/usr/bin/wc"
# sanity checks
if test -z "$BASH" ; then
printf "$SCRIPT:$LINENO: please run this script with the BASH shell\n" >&2
exit 192
fi
if test ! -x "$who" ; then
printf "$SCRIPT:$LINENO: The command $who is not available - aborting\n" >&2
exit 192
fi
if test ! -x "$sync" ; then
printf "$SCRIPT:$LINENO: the command $sync is not available - aborting\n">&2
exit 192
fi
if test ! -x "$wc" ; then
printf "$SCRIPT:$LINENO: the command $wc is not available - aborting\n" >&2
exit 192
fi
USERS = `$who | $wc -l`
if [ $USERS -eq 0 ] ; then
$sync
fi
exit 0
When I run it, I get the following error:
hello.sh: line 32: USERS: command not found
hello.sh: line 33: [: -eq: unary operator expected
I don't really know what I'm doing wrong. Am I not allowed to assign USERS to a the output of a command line in that fashion? If I run that line in the command line, it doesn't work either. Any ideas?
Thanks
remove the spaces around the assignment =:
USERS=`$who | $wc -l`
Or it will be interpreted as a command USERS with the two parameters = and `%who | $wc -l`
Replace
USERS = `$who | $wc -l`
with
USERS=`$who | $wc -l`
In Bash (in fact in many shells) you can't have spaces between a variable name and the symbol =
in this case you need to write
USERS=`command`
or
USERS=$(command)
A variable sometimes act as a C++ Macro. If the variable USERS are empty and you type this:
if [ $USERS -eq 0 ] ; then
it will be interpreted like
if [ -eq 0 ] ; then
and the -eq is not a unary operator. to make it right you need write:
if [ "$USERS" -eq 0 ] ; then
to be interpreted
if [ "" -eq 0 ] ; then