Pino Toscano
2016-Mar-22 14:48 UTC
[Libguestfs] [PATCH] appliance: use bash features for string matching in files
Read the content of /proc/cmdline using bash features, and use its
[[ ... ]] expression to find texts in a variable.
This shaves off 5 grep invocations.
---
appliance/init | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/appliance/init b/appliance/init
index f6fe9b9..8d662fa 100755
--- a/appliance/init
+++ b/appliance/init
@@ -75,7 +75,9 @@ $UDEVD --daemon #--debug
udevadm trigger
udevadm settle --timeout=600
-if grep -sq selinux=1 /proc/cmdline; then
+cmdline=$(</proc/cmdline)
+
+if [[ $cmdline == *selinux=1* ]]; then
mount -t selinuxfs none /sys/fs/selinux
fi
@@ -91,16 +93,16 @@ shopt -u nullglob
hwclock -u -s
# Parse the kernel command line.
-if grep -sq guestfs_verbose=1 /proc/cmdline; then
+if [[ $cmdline == *guestfs_verbose=1* ]]; then
guestfs_verbose=1
fi
-if grep -sq guestfs_network=1 /proc/cmdline; then
+if [[ $cmdline == *guestfs_network=1* ]]; then
guestfs_network=1
fi
-if grep -sq guestfs_rescue=1 /proc/cmdline; then
+if [[ $cmdline == *guestfs_rescue=1* ]]; then
guestfs_rescue=1
fi
-if grep -sq guestfs_noreboot=1 /proc/cmdline; then
+if [[ $cmdline == *guestfs_noreboot=1* ]]; then
guestfs_noreboot=1
fi
eval `grep -Eo 'guestfs_channel=[^[:space:]]+' /proc/cmdline`
--
2.5.5
Richard W.M. Jones
2016-Mar-22 18:59 UTC
Re: [Libguestfs] [PATCH] appliance: use bash features for string matching in files
On Tue, Mar 22, 2016 at 03:48:53PM +0100, Pino Toscano wrote:> Read the content of /proc/cmdline using bash features, and use its > [[ ... ]] expression to find texts in a variable. > > This shaves off 5 grep invocations. > --- > appliance/init | 12 +++++++----- > 1 file changed, 7 insertions(+), 5 deletions(-) > > diff --git a/appliance/init b/appliance/init > index f6fe9b9..8d662fa 100755 > --- a/appliance/init > +++ b/appliance/init > @@ -75,7 +75,9 @@ $UDEVD --daemon #--debug > udevadm trigger > udevadm settle --timeout=600 > > -if grep -sq selinux=1 /proc/cmdline; then > +cmdline=$(</proc/cmdline) > + > +if [[ $cmdline == *selinux=1* ]]; then > mount -t selinuxfs none /sys/fs/selinux > fi > > @@ -91,16 +93,16 @@ shopt -u nullglob > hwclock -u -s > > # Parse the kernel command line. > -if grep -sq guestfs_verbose=1 /proc/cmdline; then > +if [[ $cmdline == *guestfs_verbose=1* ]]; then > guestfs_verbose=1 > fi > -if grep -sq guestfs_network=1 /proc/cmdline; then > +if [[ $cmdline == *guestfs_network=1* ]]; then > guestfs_network=1 > fi > -if grep -sq guestfs_rescue=1 /proc/cmdline; then > +if [[ $cmdline == *guestfs_rescue=1* ]]; then > guestfs_rescue=1 > fi > -if grep -sq guestfs_noreboot=1 /proc/cmdline; then > +if [[ $cmdline == *guestfs_noreboot=1* ]]; then > guestfs_noreboot=1 > fi > eval `grep -Eo 'guestfs_channel=[^[:space:]]+' /proc/cmdline`ACK. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top